# Should I be using Z-tests or T-Tests for my scientific data?

I've conducted a survey for my thesis where I ask a series of questions of the format:

A statement relating to the experiment

Then the participants answer strongly disagree (1) --> strongly agree (5)

I have 14 responses and two groups, one control and one experimental (7) in each. With the answers to each of these questions, I have checked for statistical significance in each question by use of a Z-test, however I was reading this morning that my data may be ordinal and small sample size, in which case I should use a T-test.

Is my initial approach valid still?

• See stats.stackexchange.com/questions/85804/… or stats.stackexchange.com/questions/61284/t-tests-vs-z-tests , but the more general question is if you should use any of those tests with this data.
– Tim
Aug 24, 2017 at 11:19
• Wouldn't fisher's exact test be a better fit here, since your answers are categorical and sample size is small? Aug 24, 2017 at 11:25
• I don't understand "one control and one experimental in each". Are you saying that controls and treatments are paired? Or did you randomly assign 14 people to two groups? Aug 24, 2017 at 11:34
• random assignment of people to two groups, so participants either did the experiment or the control. Aug 24, 2017 at 11:36
• Why would ordinal data suggest a t-test? Aug 24, 2017 at 12:29