Dear Contributors
I have a problem with the collection of data from the results of a test.
I need to perform a comparative test over groups of data , recall the value
of the pvalue and create a table.
My problem is in the way to replicate the analysis over and over again over
subsets of data according to a condition.
I have this database, called y:
gg       t1     t2        d
 40      1      1         2
 50     2       2         1
 45     1       3         1
 49     2       1         1
 5       2       1         3
 40     1       1         2

where gg takes values from 1 to 100, t1 and t2 have values in (1,2,3) and d
in (0,1,2,3)
I want to perform tests on the values of gg according to the conditions that

d==0 , compare values of gg when t1==1 with values of gg when t1==3
d==1 , compare values of gg when t1==1 with values of gg when t1==3
d==2 , compare values of gg when t1==1 with values of gg when t1==3
..
then
d==0 , compare values of gg when t2==1 with values of gg when t2==3
d==1...


then collect the data of a statistics and create a table.
The procedure i followed is to create sub datasets called m0,m1,m2,m3
corresponding
to the values of d, i.e.

m0<- y[y$d==0,c(7,17,18,19)]
m1<- y[y$d==1,c(7,17,18,19)]
m2<- y[y$d==2,c(7,17,18,19)]
m3<- y[y$d==3,c(7,17,18,19)]

then perform the test as follows:

x1<-wilcox.test(m0[m0$t1==1,1],m0[m0$t1==3,1],correct=FALSE, exact=FALSE,
conf.int=TRUE,alternative = c("g"))   #ABC   ID
x2<-  wilcox.test(m1[m1$t1==1,1],m1[m1$t1==3,1],correct=FALSE, exact=FALSE,
conf.int=TRUE,alternative = c("g"))
 x3<-  wilcox.test(m2[m2$t1==1,1],m2[m2$t1==3,1],correct=FALSE, exact=FALSE,
conf.int=TRUE,alternative = c("g"))
x4<- wilcox.test(m3[m3$t1==1,1],m3[m3$t1==3,1],correct=FALSE, exact=FALSE,
conf.int=TRUE,alternative = c("g"))

each of these tests will create an object, say x and then I extract the
value statistics using
x$statistics.

How to automatize this?
Thank you for any help you can provide.
Francesca

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