I read this SO question and that one, but still could not solve my problem. I have the following data.table which includes only a few of my total columns and rows of my data.table.
library(data.table)
structure(list(Patient = c("MB108", "MB108", "MB108", "MB108",
"MB108", "MB108", "MB108", "MB108", "MB108", "MB108"), Visit = c(1,
1, 1, 1, 9, 9, 9, 9, 12, 12), Stimulation = c("NC", "SEB", "PPD",
"E6C10", "NC", "SEB", "PPD", "E6C10", "NC", "SEB"), `CD38 ` = c(83.3,
63.4, 83.2, 91.5, 90.9, 70.9, 71, 88.4, 41.7, 47.9)), .Names = c("Patient",
"Visit", "Stimulation", "CD38 "), class = c("data.table", "data.frame"
), row.names = c(NA, -10L), .internal.selfref = <pointer: 0x102806578>)
I would like to do a t.test on column 4 when visit is 1 and when visit is 9. I checked for NAs as well as the length of both columns.
Thanks for any help!
#na.omit(boolean_dt3)
#print(length(unlist(boolean_dt3[Visit== 1,4, with = FALSE])))
#print(length(unlist(boolean_dt3[Visit== 9,4, with = FALSE])))
wilcox.test( unlist(boolean_dt3[Visit== 1,4, with = FALSE])~ unlist(boolean_dt3[Visit== 9,4, with = FALSE]) , paired = T, correct=FALSE)