[Minitab] I am pretty confused: t test or z test

SadieKhan

TS Contributor
#1
I am pretty confused taking minitab t test or z test
as in a post , Dason said that n=30 for determining t test or z test is lame, now I have to calculate CI in minitab, and my sample size is 24, and I am totally confused whether to use t test or not..
since I tried z test and t test as well..and answer is different.
any help?
 

Dason

Ambassador to the humans
#2
Re: I am pretty confused taking minitab t test or z test

My objection was that if we don't know the true standard deviation we should ALWAYS use the t-test. But you can make these decisions for yourself. Stats is an art just as much as it is a science. I just feel that there's no reason to use a z-test if you don't know the true standard deviation (Especially if you're using a stats program to do everything for you!)