[R] output of mars() in package mda; how do I read the pairwise interaction terms from the output?

Jude Ryan juderyan at tcindex.com
Tue May 24 22:53:16 CEST 2005


Hi,

I have run mars() with the default degree=1, and have constructed 
splines which are similar to what I would get from Salford System's 
MARS. I then use these splines as potential predictors, along with 
rpart( ) terminal nodes and other potential predictors, in logistic 
regression in SAS. The output of mars() and the splines I created are 
shown below (pardon the lengthy output):

 > names(pchresp)
 [1] "ord_flag"         "OI_lodlrsize_cnt" "DI_diff_wo_arch"  
"DI_Days_s_2l_wo"
 [5] "DI_wo_rec_count"  "DH_diff_wo_arch"  "DH_Days_s_l_wo"   
"DH_tot_loss_amt"
 [9] "DH_wo_rec_count"  "DH_Avg_loss_amt"  "DA_diff_wo_arch"  "DA_max_loss"
[13] "DA_Days_s_l_wo"   "DA_Days_s_2l_wo"  "DA_wo_rec_count"  "CZ_cen65"
[17] "CZ_cen78"         "CZ_cen86"         "CZ_cen98"         "CZ_cen99"
[21] "CZ_cen132"        "CZ_cen232"        "CZ_cen236"        "CZ_cen247"
[25] "CZ_cen272"        "CZ_cen274"        "CZ_cen287"        "CZ_cen335"
[29] "CZ_cen337"        "CZ_cen370"        "CZ_cen371"        "CZ_cen373"
[33] "CZ_cen377"        "CZ_cen419"        "CZ_cen509"        "CZ_cen569"
[37] "CZ_cen638"        "CZ_cen695"        "CZ_cen696"        "CZ_cen698"
[41] "CZ_cen700"        "CZ_cen701"        "CZ_cen702"        "DZ9_rec"
[45] "log25"            "DZ5_rec"          "DZ5_str"          "DZ1_pob"
[49] "alor"             "ihcfbalratio"     "cgsbalratio"      "cgsbalpaid"
[53] "oxlogit_new"      "nslogit_new"      "sclogit_new"      "hit"
[57] "II_Find_Income2"  "II_SESI2"
 >
 > y <- pchresp[, c(1)]
 > x <- pchresp[, -c(1)]
 >
 > m1 <- mars(x, y)
 >
 > showcuts <- function(obj)
+ {
+   tmp <- obj$cuts[obj$sel, ]
+   dimnames(tmp) <- list(NULL, dimnames(x)[[2]])
+   tmp
+ }
 >
 > showcuts(m1)
      OI_lodlrsize_cnt DI_diff_wo_arch DI_Days_s_2l_wo DI_wo_rec_count
 [1,]                0               0               0               0
 [2,]                0               0               0               0
 [3,]                0               0               0               0
 [4,]                0               0               0               1
 [5,]                0               0               0               0
 [6,]                0               0               0               0
 [7,]                0               0               0               0
 [8,]                0               0               0               0
 [9,]                0               0               0               0
[10,]                0               0               0               0
[11,]                0               0               0               0
[12,]                0               0               0               0
[13,]                0               0               0               0
[14,]                0               0               0               0
[15,]                0               0               0               0
[16,]                0               0               0               0
[17,]                0               0               0               0
[18,]                0               0               0               0
[19,]                0               0               0               0
[20,]                0               0               0               0
[21,]                0               0               0               0
[22,]                0               0               0               0
      DH_diff_wo_arch DH_Days_s_l_wo DH_tot_loss_amt DH_wo_rec_count
 [1,]               0              0               0               0
 [2,]               0              0               0               0
 [3,]               0              0               0               0
 [4,]               0              0               0               0
 [5,]               0              0               0               0
 [6,]               0              0               0               0
 [7,]               0              0               0               0
 [8,]               0              0               0               0
 [9,]               0              0               0               0
[10,]               0              0               0               0
[11,]               0              0               0               0
[12,]               0              0               0               0
[13,]               0              0               0               0
[14,]               0              0               0               0
[15,]               0              0               0               0
[16,]               0              0               0               0
[17,]               0              0               0               0
[18,]               0              0               0               0
[19,]               0              0               0               0
[20,]               0              0               0               0
[21,]            1917              0               0               0
[22,]               0           1735               0               0
      DH_Avg_loss_amt DA_diff_wo_arch DA_max_loss DA_Days_s_l_wo
 [1,]               0               0           0              0
 [2,]               0               0           0              0
 [3,]               0               0           0              0
 [4,]               0               0           0              0
 [5,]               0               0           0              0
 [6,]               0               0           0              0
 [7,]               0               0           0              0
 [8,]               0               0           0              0
 [9,]               0               0           0              0
[10,]               0               0           0              0
[11,]               0               0           0              0
[12,]               0               0           0              0
[13,]               0               0           0              0
[14,]               0               0           0              0
[15,]               0               0           0              0
[16,]               0               0           0              0
[17,]               0               0           0              0
[18,]               0               0           0              0
[19,]               0               0           0              0
[20,]               0               0           0              0
[21,]               0               0           0              0
[22,]               0               0           0              0
      DA_Days_s_2l_wo DA_wo_rec_count CZ_cen65 CZ_cen78 CZ_cen86 CZ_cen98
 [1,]               0               0        0        0        0        0
 [2,]               0               0        0        0        0        0
 [3,]               0               0        0        0        0        0
 [4,]               0               0        0        0        0        0
 [5,]               0               0        0        0        0        0
 [6,]               0               0        0        0        0        0
 [7,]               0               0        0        0        0        0
 [8,]               0               0        0        0        0        0
 [9,]               0               0        0        0        0        0
[10,]               0               0        0        0        0        0
[11,]               0               0        0        0        0        0
[12,]               0               0        0        0        0        0
[13,]               0               0        0        0        0        0
[14,]               0               0        0        0        0        0
[15,]               0               0        0        0        0        0
[16,]               0               0        0        0        0        0
[17,]               0               0        0        0        0        0
[18,]               0               0        0        0        0        0
[19,]               0               0        0        0        0        0
[20,]               0               0        0        0        0        0
[21,]               0               0        0        0        0        0
[22,]               0               0        0        0        0        0
      CZ_cen99 CZ_cen132 CZ_cen232 CZ_cen236 CZ_cen247 CZ_cen272 CZ_cen274
 [1,]        0         0         0         0 0.0000000         0         0
 [2,]        0         0         0         0 0.0000000         0         0
 [3,]        0         0         0         0 0.0000000         0         0
 [4,]        0         0         0         0 0.0000000         0         0
 [5,]        0         0         0         0 0.0000000         0         0
 [6,]        0         0         0         0 0.0000000         0         0
 [7,]        0         0         0         0 0.0000000         0         0
 [8,]        0         0         0         0 0.0000000         0         0
 [9,]        0         0         0         0 0.0000000         0         0
[10,]        0         0         0         0 0.0000000         0         0
[11,]        0         0         0         0 0.0000000         0         0
[12,]        0         0         0         0 0.0000000         0         0
[13,]        0         0         0         0 0.0000000         0         0
[14,]        0         0         0         0 0.9069767         0         0
[15,]        0         0         0         0 0.9069767         0         0
[16,]        0         0         0         0 0.0000000         0         0
[17,]        0         0         0         0 0.0000000         0         0
[18,]        0         0         0         0 0.0000000         0         0
[19,]        0         0         0         0 0.0000000         0         0
[20,]        0         0         0         0 0.0000000         0         0
[21,]        0         0         0         0 0.0000000         0         0
[22,]        0         0         0         0 0.0000000         0         0
      CZ_cen287 CZ_cen335 CZ_cen337 CZ_cen370 CZ_cen371 CZ_cen373 CZ_cen377
 [1,]         0         0         0         0         0         0         0
 [2,]         0         0         0         0         0         0         0
 [3,]         0         0         0         0         0         0         0
 [4,]         0         0         0         0         0         0         0
 [5,]         0         0         0         0         0         0         0
 [6,]         0         0         0         0         0         0         0
 [7,]         0         0         0         0         0         0         0
 [8,]         0         0         0         0         0         0         0
 [9,]         0         0         0         0         0         0         0
[10,]         0         0         0         0         0         0         0
[11,]         0         0         0         0         0         0         0
[12,]         0         0         0         0         0         0         0
[13,]     32857         0         0         0         0         0         0
[14,]         0         0         0         0         0         0         0
[15,]         0         0         0         0         0         0         0
[16,]         0         0         0         0         0         0         0
[17,]         0         0         0         0         0         0         0
[18,]         0         0         0         0         0         0         0
[19,]         0         0         0         0         0         0         0
[20,]         0         0         0         0         0         0         0
[21,]         0         0         0         0         0         0         0
[22,]         0         0         0         0         0         0         0
      CZ_cen419 CZ_cen509 CZ_cen569 CZ_cen638 CZ_cen695 CZ_cen696 CZ_cen698
 [1,]         0         0   0.00000         0         0         0         0
 [2,]         0         0   0.00000         0         0         0         0
 [3,]         0         0   0.00000         0         0         0         0
 [4,]         0         0   0.00000         0         0         0         0
 [5,]         0         0   0.00000         0         0         0         0
 [6,]         0         0   0.00000         0         0         0         0
 [7,]         0         0   0.00000         0         0         0         0
 [8,]         0         0   0.00000         0         0         0         0
 [9,]         0         0   0.00000         0         0         0         0
[10,]         0         0   0.00000         0         0         0         0
[11,]         0         0   0.00000         0         0         0         0
[12,]         0         0   0.00000         0         0         0         0
[13,]         0         0   0.00000         0         0         0         0
[14,]         0         0   0.00000         0         0         0         0
[15,]         0         0   0.00000         0         0         0         0
[16,]         0         0  11.07613         0         0         0         0
[17,]         0         0   0.00000         0         0         0         0
[18,]         0         0   0.00000         0         0         0        30
[19,]         0         0   0.00000         0         0         0        30
[20,]         0         0   0.00000         0         0         0         0
[21,]         0         0   0.00000         0         0         0         0
[22,]         0         0   0.00000         0         0         0         0
      CZ_cen700 CZ_cen701 CZ_cen702 DZ9_rec log25 DZ5_rec DZ5_str 
DZ1_pob alor
 [1,]         0         0         0       0     0       0       0       
0    0
 [2,]         0         0         0       0     0       0       0       
0    0
 [3,]         0         0         0       0     0       0       0       
0    0
 [4,]         0         0         0       0     0       0       0       
0    0
 [5,]         0         0         0       0     0       0       0       
0    0
 [6,]         0         0         0       0     0       0       0       
0    0
 [7,]         0         0         0       0     0       0       0       
0   32
 [8,]         0         0         0       0     0       0       0       
0    0
 [9,]         0         0         0       0     0       0       0       
0    0
[10,]         0         0         0       0     0       0       0       
0    0
[11,]         0         0        38       0     0       0       0       
0    0
[12,]         0         0        38       0     0       0       0       
0    0
[13,]         0         0         0       0     0       0       0       
0    0
[14,]         0         0         0       0     0       0       0       
0    0
[15,]         0         0         0       0     0       0       0       
0    0
[16,]         0         0         0       0     0       0       0       
0    0
[17,]         0         0         0       0     0       0       0       
0    0
[18,]         0         0         0       0     0       0       0       
0    0
[19,]         0         0         0       0     0       0       0       
0    0
[20,]         0         0         0       0     0       0       0       
0    0
[21,]         0         0         0       0     0       0       0       
0    0
[22,]         0         0         0       0     0       0       0       
0    0
      ihcfbalratio cgsbalratio cgsbalpaid oxlogit_new nslogit_new 
sclogit_new
 [1,]            0     0.00000          0           0     
0.00000           0
 [2,]            0     0.00000          0           0     
1.28535           0
 [3,]            0     0.00000          0           0     
1.28535           0
 [4,]            0     0.00000          0           0     
0.00000           0
 [5,]            0     0.00000          0           0     
0.00000           0
 [6,]            0    16.03509          0           0     
0.00000           0
 [7,]            0     0.00000          0           0     
0.00000           0
 [8,]            0     0.00000          0           0     
0.00000           0
 [9,]            0     0.00000          0           0     
0.00000           0
[10,]            0     0.00000          0           0     
0.00000           0
[11,]            0     0.00000          0           0     
0.00000           0
[12,]            0     0.00000          0           0     
0.00000           0
[13,]            0     0.00000          0           0     
0.00000           0
[14,]            0     0.00000          0           0     
0.00000           0
[15,]            0     0.00000          0           0     
0.00000           0
[16,]            0     0.00000          0           0     
0.00000           0
[17,]            0     0.00000          0           0     
0.00000           0
[18,]            0     0.00000          0           0     
0.00000           0
[19,]            0     0.00000          0           0     
0.00000           0
[20,]            0     0.00000          0           0     
0.00000           0
[21,]            0     0.00000          0           0     
0.00000           0
[22,]            0     0.00000          0           0     
0.00000           0
      hit II_Find_Income2 II_SESI2
 [1,]   0               0        0
 [2,]   0               0        0
 [3,]   0               0        0
 [4,]   0               0        0
 [5,]   0               0        0
 [6,]   0               0        0
 [7,]   0               0        0
 [8,]   0               0        0
 [9,]   0           26000        0
[10,]   0           26000        0
[11,]   0               0        0
[12,]   0               0        0
[13,]   0               0        0
[14,]   0               0        0
[15,]   0               0        0
[16,]   0               0        0
[17,]   0           71000        0
[18,]   0               0        0
[19,]   0               0        0
[20,]   0               0       27
[21,]   0               0        0
[22,]   0               0        0
 >

The mars splines I created are:

DH_diff_wo_arch_sp1 = max(0, DH_diff_wo_arch - 1917);
DH_Days_s_l_wo_sp1  = max(0, DH_Days_s_l_wo - 1735);
CZ_cen247_sp1       = max(0, CZ_cen247 - 0.9069767);
CZ_cen287_sp1       = max(0, CZ_cen287 - 32857);
CZ_cen569_sp1       = max(0, CZ_cen569 - 11.07613);
CZ_cen698_sp1       = max(0, CZ_cen698 - 30);
CZ_cen702_sp1       = max(0, CZ_cen702 - 38);
alor_sp1            = max(0, alor - 32);
cgsbalratio_sp1     = max(0, cgsbalratio - 16.03509);
nslogit_new_sp1     = max(0, nslogit_new - 1.28535);
II_Find_Income2_sp1 = max(0, II_Find_Income2 - 26000);
II_Find_Income2_sp2 = max(0, II_Find_Income2 - 71000);
II_SESI2_sp1        = max(0, II_SESI2 - 27);

My next run of mars( ) uses degree=2.

 > m2 <- mars(x, y, degree=2)
 >
 > showcuts(m2)
      OI_lodlrsize_cnt DI_diff_wo_arch DI_Days_s_2l_wo DI_wo_rec_count
 [1,]                0               0               0               0
 [2,]                0               0               0               1
 [3,]                0               0               0               1
 [4,]                0               0               0               1
 [5,]                0               0               0               0
 [6,]                0               0               0               1
 [7,]                0               0               0               1
 [8,]                0               0               0               1
 [9,]                0               0               0               0
[10,]                0               0               0               0
[11,]                0               0               0               0
[12,]                0               0               0               0
[13,]                0               0               0               0
[14,]                0               0               0               0
[15,]                0               0               0               0
[16,]                0               0               0               0
[17,]                0               0               0               0
[18,]                0               0               0               0
[19,]                0               0               0               0
[20,]                0               0               0               0
[21,]                0               0               0               0
[22,]                0               0               0               0
[23,]                0               0               0               1
[24,]                0               0               0               0
[25,]                0               0               0               0
[26,]                0               0               0               0
[27,]                0               0               0               0
[28,]                0               0               0               0
[29,]                0               0               0               0
[30,]                0               0               0               0
[31,]                0               0               0               0
[32,]                0               0               0               0
[33,]                0               0               0               0
[34,]                0               0               0               0
      DH_diff_wo_arch DH_Days_s_l_wo DH_tot_loss_amt DH_wo_rec_count
 [1,]               0              0               0               0
 [2,]               0              0               0               0
 [3,]               0              0               0               0
 [4,]               0              0               0               0
 [5,]               0              0               0               0
 [6,]               0              0               0               0
 [7,]               0              0               0               0
 [8,]               0              0               0               0
 [9,]               0              0               0               0
[10,]               0              0               0               0
[11,]               0              0               0               0
[12,]               0              0               0               0
[13,]               0              0               0               0
[14,]               0              0               0               0
[15,]               0              0               0               0
[16,]               0              0               0               0
[17,]               0              0               0               0
[18,]               0              0               0               0
[19,]               0              0               0               0
[20,]               0              0               0               0
[21,]               0              0               0               0
[22,]            1917              0               0               0
[23,]               0              0               0               0
[24,]               0              0               0               0
[25,]               0              0               0               0
[26,]               0              0               0               0
[27,]               0              0               0               0
[28,]            1917              0               0               0
[29,]               0              0               0               0
[30,]               0              0               0               0
[31,]               0              0               0               0
[32,]               0              0               0               0
[33,]               0              0               0               0
[34,]               0              0               0               0
      DH_Avg_loss_amt DA_diff_wo_arch DA_max_loss DA_Days_s_l_wo
 [1,]               0               0           0              0
 [2,]               0               0           0              0
 [3,]               0               0           0              0
 [4,]               0               0           0              0
 [5,]               0               0           0              0
 [6,]               0               0           0              0
 [7,]               0               0           0              0
 [8,]               0               0           0              0
 [9,]               0               0           0              0
[10,]               0               0           0              0
[11,]               0               0           0              0
[12,]               0               0           0              0
[13,]               0               0           0              0
[14,]               0               0           0              0
[15,]               0               0           0              0
[16,]               0               0           0              0
[17,]               0               0           0              0
[18,]               0               0           0              0
[19,]               0               0           0              0
[20,]               0               0           0              0
[21,]               0               0           0           1856
[22,]               0               0           0              0
[23,]               0             943           0              0
[24,]               0               0           0              0
[25,]               0               0           0              0
[26,]               0               0           0              0
[27,]               0               0           0              0
[28,]               0               0           0              0
[29,]               0               0           0              0
[30,]               0               0           0              0
[31,]               0               0           0              0
[32,]               0               0           0              0
[33,]               0               0           0              0
[34,]               0               0           0              0
      DA_Days_s_2l_wo DA_wo_rec_count CZ_cen65  CZ_cen78 CZ_cen86 CZ_cen98
 [1,]               0               0        0 0.0000000        0        0
 [2,]               0               0        0 0.0000000        0        0
 [3,]               0               0        0 0.0000000        0        0
 [4,]               0               0        0 0.0000000        0        0
 [5,]               0               0        0 0.0000000        0        0
 [6,]               0               0        0 0.0000000        0        0
 [7,]               0               0        0 0.0000000        0        0
 [8,]               0               0        0 0.0000000        0        0
 [9,]               0               0        0 0.0000000        0        0
[10,]               0               0        0 0.0000000        0        0
[11,]               0               0        0 0.0000000        0        0
[12,]               0               0        0 0.0000000        0        0
[13,]               0               0        0 0.0000000        0        0
[14,]               0               0        0 0.0000000        0        0
[15,]               0               0        0 0.0000000        0        0
[16,]               0               0        0 0.0000000        0        0
[17,]               0               0        0 0.0000000        0        0
[18,]               0               0        0 0.0000000        0        0
[19,]               0               0        0 0.4242424        0        0
[20,]               0               0        0 0.0000000        0        0
[21,]               0               0        0 0.0000000        0        0
[22,]               0               0        0 0.0000000        0        0
[23,]               0               0        0 0.0000000        0        0
[24,]               0               0        0 0.0000000        0        0
[25,]               0               0        0 0.0000000        0        0
[26,]               0               0        0 0.0000000        0        0
[27,]               0               0        0 0.0000000        0        0
[28,]               0               0        0 0.0000000        0        0
[29,]               0               0        0 0.0000000        0        0
[30,]               0               0        0 0.0000000        0        0
[31,]               0               0        0 0.0000000        0        0
[32,]               0               0        0 0.0000000        0        0
[33,]               0               0        0 0.0000000        0        0
[34,]               0               0        0 0.0000000        0        0
      CZ_cen99 CZ_cen132 CZ_cen232 CZ_cen236 CZ_cen247 CZ_cen272 CZ_cen274
 [1,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [2,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [3,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [4,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [5,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [6,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [7,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [8,]        0 0.0000000         0 0.0000000 0.0000000         0         0
 [9,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[10,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[11,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[12,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[13,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[14,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[15,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[16,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[17,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[18,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[19,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[20,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[21,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[22,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[23,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[24,]        0 0.4729299         0 0.0000000 0.0000000         0         0
[25,]        0 0.4729299         0 0.0000000 0.0000000         0         0
[26,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[27,]        0 0.0000000         0 0.4290323 0.0000000         0         0
[28,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[29,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[30,]        0 0.0000000         0 0.0000000 0.9074286         0         0
[31,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[32,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[33,]        0 0.0000000         0 0.0000000 0.0000000         0         0
[34,]        0 0.0000000         0 0.0000000 0.0000000         0         0
      CZ_cen287 CZ_cen335 CZ_cen337 CZ_cen370 CZ_cen371 CZ_cen373 CZ_cen377
 [1,]         0         0         0         0         0 0.0000000         0
 [2,]         0         0         0         0         0 0.0000000         0
 [3,]         0         0         0         0         0 0.0000000         0
 [4,]         0         0         0         0         0 0.0000000         0
 [5,]         0         0         0         0         0 0.0000000         0
 [6,]         0         0         0         0         0 0.0000000         0
 [7,]         0         0         0         0         0 0.0000000         0
 [8,]         0         0         0         0         0 0.0000000         0
 [9,]         0         0         0         0         0 0.0000000         0
[10,]     36324         0         0         0         0 0.0000000         0
[11,]     36324         0         0         0         0 0.0000000         0
[12,]     36324         0         0         0         0 0.0000000         0
[13,]     36324         0         0         0         0 0.0000000         0
[14,]         0         0         0         0         0 0.0000000         0
[15,]         0         0         0         0         0 0.0000000         0
[16,]         0         0         0         0         0 0.0000000         0
[17,]         0         0         0         0         0 0.0000000         0
[18,]         0         0         0         0         0 0.0000000         0
[19,]         0         0         0         0         0 0.0000000         0
[20,]         0         0         0         0         0 0.0000000         0
[21,]         0         0         0         0         0 0.0000000         0
[22,]         0         0         0         0         0 0.0000000         0
[23,]         0         0         0         0         0 0.0000000         0
[24,]         0         0         0         0         0 0.0000000         0
[25,]         0         0         0         0         0 0.0000000         0
[26,]         0         0         0         0         0 0.0000000         0
[27,]         0         0         0         0         0 0.0000000         0
[28,]         0         0         0         0         0 0.0000000         0
[29,]         0         0         0         0         0 0.0000000         0
[30,]     14306         0         0         0         0 0.0000000         0
[31,]         0         0         0         0         0 0.0000000         0
[32,]         0         0         0         0         0 0.0000000         0
[33,]         0         0         0         0         0 0.0000000         0
[34,]         0         0         0         0         0 0.2213115         0
      CZ_cen419 CZ_cen509 CZ_cen569 CZ_cen638 CZ_cen695 CZ_cen696 CZ_cen698
 [1,]         0         0   0.00000         0         0         0         0
 [2,]         0         0   0.00000         0         0         0         0
 [3,]         0         0   0.00000         0         0         0         0
 [4,]         0         0   0.00000         0         0         0         0
 [5,]         0         0   0.00000         0         0         0         0
 [6,]         0         0   0.00000         0         0         0         0
 [7,]         0         0   0.00000         0         0         0         0
 [8,]         0         0   0.00000         0         0         0         0
 [9,]         0         0   0.00000         0         0         0         0
[10,]         0         0   0.00000         0         0         0         0
[11,]         0         0   0.00000         0         0         0         0
[12,]         0         0   0.00000         0         0         0        31
[13,]         0         0   0.00000         0         0         0        31
[14,]         0         0   0.00000         0         0         0         0
[15,]         0         0  12.92770         0         0         0         0
[16,]         0         0   0.00000         0         0         0         0
[17,]         0         0   0.00000         0         0         0         0
[18,]         0         0   0.00000         0         0         0         0
[19,]         0         0   0.00000         0         0         0         0
[20,]         0         0   0.00000         0         0         0         0
[21,]         0         0   0.00000         0         0         0         0
[22,]         0         0   0.00000         0         0         0         0
[23,]         0         0   0.00000         0         0         0         0
[24,]         0         0   0.00000         0         0         0         0
[25,]         0         0   0.00000         0         0         0         0
[26,]         0         0   0.00000         0         0         0         0
[27,]         0         0   0.00000         0         0         0         0
[28,]         0         0   0.00000         0         0         0         0
[29,]         0         0   0.00000         0         0         0         0
[30,]         0         0   0.00000         0         0         0         0
[31,]         0         0   0.00000         0         0         0         0
[32,]         0         0   0.00000         0         0         0         0
[33,]         0         0   0.00000         0         0         0         0
[34,]         0         0   0.00000         0         0         0         0
      CZ_cen700 CZ_cen701 CZ_cen702 DZ9_rec   log25 DZ5_rec DZ5_str DZ1_pob
 [1,]         0         0         0       0 0.00000       0       0       0
 [2,]         0         0         0       0 0.00000       0       0       0
 [3,]         0         0         0       0 0.00000       0       0       0
 [4,]         0         0         0       0 0.00000       0       0       0
 [5,]         0         0         0       0 0.00000       0       0       0
 [6,]         0         0         0       0 0.00000       0       0       0
 [7,]         0         0         0       0 0.00000       0       0       0
 [8,]         0         0         0       0 0.00000       0       0       0
 [9,]         0         0         0       0 2.17021       0       0       0
[10,]         0         0         0       0 0.00000       0       0       0
[11,]         0         0         0       0 0.00000       0       0       0
[12,]         0         0         0       0 0.00000       0       0       0
[13,]         0         0         0       0 0.00000       0       0       0
[14,]         0         0         0       0 0.00000       0       0       0
[15,]         0         0         0       0 0.00000       0       0       0
[16,]        93         0         0       0 0.00000       0       0       0
[17,]        93         0         0       0 0.00000       0       0       0
[18,]         0         0         0       0 0.00000       0       0       0
[19,]         0         0         0       0 0.00000       0       0       0
[20,]         0         0         0       0 0.00000       0       0       0
[21,]         0         0         0       0 0.00000       0       0       0
[22,]         0         0         0       0 0.00000       0       0       0
[23,]         0         0         0       0 0.00000       0       0       0
[24,]         0         0         0       0 0.00000       0       0       0
[25,]         0         0         0       0 0.00000       0       0       0
[26,]         0         0         0       0 0.00000       0       0       0
[27,]         0         0         0       0 0.00000       0       0       0
[28,]         0         0        38       0 0.00000       0       0       0
[29,]         0         0         0       0 0.00000    8405       0       0
[30,]         0         0         0       0 0.00000       0       0       0
[31,]         0         0         0       0 2.45773       0       0       0
[32,]         0         0         0       0 0.00000       0       0       0
[33,]         0         0         0       0 0.00000       0       0       0
[34,]         0         0         0       0 0.00000       0       0       0
      alor ihcfbalratio cgsbalratio cgsbalpaid oxlogit_new nslogit_new
 [1,]    0            0     0.00000          0           0     0.00000
 [2,]    0            0     0.00000          0           0     0.00000
 [3,]    0            0     0.00000          0           0     0.00000
 [4,]    0            0     0.00000          0           0     0.00000
 [5,]    0            0    16.03509          0           0     0.00000
 [6,]   32            0     0.00000          0           0     0.00000
 [7,]    0            0     0.00000          0           0     0.00000
 [8,]    0            0     0.00000          0           0     0.00000
 [9,]    0            0    16.03509          0           0     0.00000
[10,]    0            0     0.00000          0           0     0.00000
[11,]    0            0     0.00000          0           0     0.00000
[12,]    0            0     0.00000          0           0     0.00000
[13,]    0            0     0.00000          0           0     0.00000
[14,]    0            0     0.00000          0           0     0.00000
[15,]    0            0     0.00000          0           0     0.00000
[16,]    0            0     0.00000          0           0     0.00000
[17,]    0            0     0.00000          0           0     0.00000
[18,]   18            0     0.00000          0           0     0.00000
[19,]    0            0    16.03509          0           0     0.00000
[20,]    0            0     0.00000          0           0     1.28535
[21,]    0            0     0.00000          0           0     1.28535
[22,]    0            0     0.00000          0           0     0.00000
[23,]    0            0     0.00000          0           0     0.00000
[24,]    0            0     0.00000          0           0     1.28535
[25,]    0            0     0.00000          0           0     1.28535
[26,]    0            0     0.00000          0           0     0.00000
[27,]    0            0     0.00000          0           0     1.28535
[28,]    0            0     0.00000          0           0     0.00000
[29,]    0            0     0.00000          0           0     0.00000
[30,]    0            0     0.00000          0           0     0.00000
[31,]    0            0     0.00000          0           0     1.28535
[32,]    0            0    16.03509          0           0     3.01888
[33,]    0            0     0.00000          0           0     1.28535
[34,]    0            0    16.03509          0           0     0.00000
      sclogit_new hit II_Find_Income2 II_SESI2
 [1,]           0   0               0        0
 [2,]           0   0               0        0
 [3,]           0   0               0        0
 [4,]           0   0               0        0
 [5,]           0   0               0        0
 [6,]           0   0               0        0
 [7,]           0   0               0       16
 [8,]           0   0               0        0
 [9,]           0   0               0        0
[10,]           0   0               0        0
[11,]           0   0               0        0
[12,]           0   0               0        0
[13,]           0   0               0        0
[14,]           0   0               0        0
[15,]           0   0               0        0
[16,]           0   0               0        0
[17,]           0   0               0        0
[18,]           0   0               0        0
[19,]           0   0               0        0
[20,]           0   0               0       27
[21,]           0   0               0        0
[22,]           0   0               0        0
[23,]           0   0               0        0
[24,]           0   0               0        0
[25,]           0   0               0        0
[26,]           0   0          122000        0
[27,]           0   0               0        0
[28,]           0   0               0        0
[29,]           0   0               0        0
[30,]           0   0               0        0
[31,]           0   0               0        0
[32,]           0   0               0        0
[33,]           0   0          225000        0
[34,]           0   0               0        0
 >

While I can construct splines in a similar manner to what I did for my 
first output, I am unable to figure out how to construct mars splines 
for the pairwise interactions I am supposed to be getting for degree=2.

The mars documentation and Venables' and Ripley's Modern Applied 
Statistics with S (pages 235 to 237) do show similar output, but not how 
to construct splines or figure out the pairwise interactions.

Any help is greatly appreciated.

Thanks in advance.

Jude Ryan




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