can anyone explain why we use the t-statistic instead of the z- statistic when conducting such tests ?
When doing paired comparison test, do we know the population variance? Is the sample size > 30? t-stats is definitely a more conservative test, so that is probably the reason why we choose it over the z-stats.
makes perfect sense ! Thanks alot
Pair comparison test is actually a test for a sample which has value derived from the difference between to dependent sample. We do not know the population variance therefore using t test is the most appropriate method. Cheers