[R-sig-ME] Error message in lme function and question about the residual plot

li li hannah.hlx at gmail.com
Thu Jun 11 19:22:04 CEST 2015


Hi all,
  I have the following data frame named "one" in which there is a
grouping factor method with three levels. The varibility is very
different among the three groups seen from the plot. I am trying to
compare three models as follows. I have the following two questions:
  1. As you can see the third model does not seem to work. I am not
sure whether it is a convergent issue.
  2. The first model doesnot take into account the variance
heterogeneity issue while the second one does. However, when I compare
the residual plot between mod1 and mod2, there is not much difference.
The residual for the second model still has much larger variance for
methods 2 and 3 than the method 1.

  Thanks very much!
  Hanna


> one
    method individual time       res
1        3         12    0 101.40000
2        3         12    3 101.50000
3        3         12    6 101.50000
4        3         12    9 101.30000
5        3         12   12 100.70000
6        3         12   15 101.00000
7        3         12   18 101.50000
14       3         10    0 101.30000
15       3         10    3 101.20000
16       3         10    6 101.50000
17       3         10    9 100.70000
18       3         10   12 101.50000
19       3         10   15 101.30000
20       3         10   18 101.30000
27       3         11    0 100.70000
28       3         11    3 101.10000
29       3         11    6 101.90000
30       3         11    9 100.80000
31       3         11   12  99.80000
32       3         11   15 100.60000
33       3         11   18 100.60000
40       3          1    0  97.50000
41       3          1    3  97.40000
42       3          1    6  97.70000
43       3          1    9  97.40000
44       3          1   12  97.30000
45       3          1   15  96.70000
46       3          1   18  96.60000
54       3          3    0  98.10000
55       3          3    3  98.50000
56       3          3    6  97.90000
57       3          3    9  97.90000
58       3          3   12  97.70000
59       3          3   15  98.00000
60       3          3   18  98.50000
67       3          6    0 100.20000
68       3          6    3  99.60000
69       3          6    6  99.90000
70       3          6    9  99.90000
71       3          6   12 100.30000
77       3          2    0  98.90000
78       3          2    3  98.90000
79       3          2    6  98.70000
80       3          2    9  98.90000
81       3          2   12  98.80000
82       3          2   15  97.80000
83       3          2   18  98.90000
90       3          4    0 100.20000
91       3          4    3  99.80000
92       3          4    6  99.50000
93       3          4    9 100.40000
96       3          5    0 100.70000
97       3          5    3 100.30000
98       3          5    6 100.70000
99       3          5    9 100.50000
102      3          7    0 100.90000
105      3          8    0  99.30000
108      3          9    0 100.20000
111      3         13    0 101.00000
114      3         14    0 100.80000
117      3         15    0 100.40000
8        2         12    0 108.00000
9        2         12   12  97.00000
21       2         10    0 112.00000
22       2         10   12  93.00000
34       2         11    0  98.00000
35       2         11   12  96.00000
47       2          1    0  94.00000
48       2          1   12 103.00000
49       2          1   18 103.00000
61       2          3    0  87.00000
62       2          3   12 105.00000
72       2          6    0 119.00000
73       2          6    3 105.00000
74       2          6   12  91.00000
84       2          2    0 105.00000
85       2          2   12 112.00000
95       2          4    0  96.00000
101      2          5    0 113.00000
104      2          7    0 106.00000
107      2          8    0  71.00000
110      2          9    0  95.00000
113      2         13    0  88.00000
116      2         14    0  86.00000
119      2         15    0  81.00000
86       1         12    0 105.90300
94       1         12   12  99.82400
10       1         12   15  91.26400
11       1         12   18  72.15000
191      1         10    0  91.14300
201      1         10   12 100.36800
211      1         10   15 104.79600
221      1         10   18 102.58200
301      1         11    0  78.32400
311      1         11   12  88.20900
321      1         11   15  95.52600
331      1         11   18 106.87200
411      1          1    0  99.04500
421      1          1   12  82.83600
431      1          1   15 116.51200
441      1          1   18  89.05600
52       1          3    0  97.81800
53       1          3   12  89.81500
541      1          3   15  82.11000
551      1          3   18  79.83400
611      1          6    0  89.06000
621      1          6   12 102.56500
701      1          2    0 112.32000
711      1          2   12 104.40000
721      1          2   15  90.06800
731      1          2   18 107.28000
781      1          4    0 125.92500
831      1          5    0  95.16000
851      1          7    0 111.28981
87       1          8    0 102.22482
89       1          9    0  91.61610
911      1         13    0 111.18053
931      1         14    0  91.70376
951      1         15    0  98.04994



library(nlme)
mod1 <- lme(fixed= res ~ method*time, random=~ 1+ time | individual, data=one)
summary(mod1)
anova(mod1)

mod2 <- lme(fixed= res ~ method*time, random=~ 1+ time | individual,
data=one, weights= varIdent(form=~1|method))
summary(mod2)
anova(mod2)

mod3 <- lme(fixed= res ~ method*time, random=~ 0+ method+ time |
individual, data=one, weights= varIdent(form=~1|assay))
summary(mod3)
anova(mod3)

par(mfrow=c(1,2))
plot(resid(mod1))
plot(resid(mod2))



More information about the R-sig-mixed-models mailing list