Why when I run the ggttest there is an error?

Question

When I run the t-test for a numeric and a dichotomous variable there in no problem and I can see the results. The problem is when I run the ggttest of the same t-test. There is an error and says that one of my variable is not found. I do not why that happens. The aml dataset I used is from package boot. Below you can see the code:

https://i.stack.imgur.com/7kuaA.png

library(gginference)
time_group.test16537 = t.test(formula = time~group,
                              data = aml,
                              alternative = "two.sided",
                              paired = FALSE,
                              var.equal = FALSE,
                              conf.level = 0.95)
    time_group.test16537


    ggttest(time_group.test16537,
            colaccept="lightsteelblue1", 
            colreject="gray84", 
            colstat="navyblue")

user_12258459 · Answer

The problem comes with these lines of code in ggttest:

datnames <- strsplit(t$data.name, splitter)
len1 <- length(eval(parse(text = datnames[[1]][1])))
len2 <- length(eval(parse(text = datnames[[1]][2])))

It tries to find the len of group and time, but it doesn't see that it came from a data.frame. Pretty bad bug...

For your situation, supposedly you have less than 30 in each group and it plots a t-distribution, so do:

library(gginference)
library(boot)
gginference:::normt(t.test(time~group,data=aml),
colaccept = "lightsteelblue1",colreject = "grey84", 
colstat = "navyblue")

user_6790870 · Answer

t.test doesn't store your data in the output so there is no way that you could extract the data from the list of the output of t.test.

The only way to use formula is:

library(gginference)
t_test <- t.test(questionnaire$pulse ~ questionnaire$gender)
ggttest(t_test)

Original answer here: How to extract the dataset from an "htest" object when using formula in r

Why when I run the ggttest there is an error?

2 Answers