
Hello,I posted this
message previously on R-help.My data is like following and there is a response variable y:Time &nbsp; &nbsp;Size &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Charge &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;Density &nbsp; &nbsp; &nbsp; &nbsp; Replication3
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp;1. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;+
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
+ &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 13
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
- &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; 1. &nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;
.. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp;
&nbsp; &nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 13
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1.
&nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; ..
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp;
&nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13 &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;high
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 1. &nbsp; &nbsp;
&nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp;
&nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; high &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp;1. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;.9 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; high &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp;13 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
- &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; high &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;13
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 2.
&nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; ..
&nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; . &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 23
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;23 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;low &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;2. &nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;
.. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp;
&nbsp; &nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 23
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; 2. &nbsp; &nbsp; &nbsp; &nbsp;.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp;low &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;23 &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; small &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; + &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;high &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
2. &nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
. &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; ..
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp;
&nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp;high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 23 &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; high &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2. &nbsp; &nbsp;
&nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp;
&nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; + &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;23
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2.
&nbsp; &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; .
&nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; ..
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp;
&nbsp; .9 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; small
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;23 &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; high
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2. &nbsp; &nbsp;
&nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; . &nbsp; &nbsp;
&nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; .. &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; . &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; . &nbsp; &nbsp; &nbsp;. &nbsp; &nbsp; &nbsp; .9
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; big &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; - &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; high &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2My code with comments:##this function selects the knotsdefault.knots &lt;-
function(x,num.knots){if
(missing(num.knots))num.knots &lt;-
max(5,min(floor(length(unique(x))/4),35))return(quantile(unique(x),seq(0,1,length=(num.knots+2))[-c(1,(num.knots+2))]))}knots &lt;-
default.knots(Time)z
&lt;- outer(Time, knots, "-")z &lt;- z * (z &gt; 0)z&lt;-z^2i.size50 &lt;-
I(Size==small)i.chargepos &lt;- I(Charge=="+")i.densitylow &lt;- I(Density==low)##Create X and Z matrices, &nbsp;I put interactions because I
wantintercept to be zero at time 0.X
&lt;- cbind( I(Time^2),Time*i.size50,Time*i.chargepos,Time*i.densitylow)Z &lt;- cbind( z, z*i.size50,
z*i.chargepos,z*i.densitylow)K &lt;- length(knots)## form blocked diagonal matrix Z
to specify which columns of Z areused for each groupblock.ind &lt;- list(1:K,
(K+1):(2*K),(2*K+1):(3*K),(3*K+1):(4*K))Z.block &lt;- list()for (i in
1:length(block.ind))Z.block[[i]] &lt;-as.formula(paste("~Z[,c(",paste(block.ind[[i]],collapse=","),")]-1"))##create dummy grouping variable
since groupedData object is required for lmegroup &lt;-
rep(1, length(Time))model.data &lt;- groupedData(y~X|group,
data=data.frame(X, y))fit &lt;- lme(y~-1+X, data=model.data, random=pdBlocked(list(pdBlocked(Z.block,pdClass="pdIdent"), pdIdent(~-1+
Replication) )),control=list(maxIter=1000, msMaxIter=1000,
niterEM=1000))It
gives error : "Error: &nbsp;getResponseFormula(el) : "Form" must be
atwo sided formula"How can I write the random part?The experiment is repeated twice (Replication 1 and 2) , hence I
thinkthat Replication should be random effect. My
replications are randomlychosen from a population and I
should make inference about thepopulation. &nbsp;I don't have a
chance to take more replications.


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