I have conducted an empirical study as a part of my master thesis. Each test subject filled out a questionnaire where some questions were regarding usability of different features. What is the best/correct way to calculate if a feature got a significant better usability score than another feature? (I used a 10-point Likert scale).
I had 14 test subjects, and I want to compare the usability score for a feature called "bubble" and a feature called "hull".
This is the scores:
Bubble: 6, 3, 7, 9, 7, 8, 7, 9, 8, 8, 6, 10, 3, 7 Hull: 9, 10, 10, 8.6154, 9, 6, 8, 10, 8, 8, 6, 10, 9, 9
(One subject did not rate "hull", I have therefore inserted the mean (8.6154) in its place.)
I have run a paired-sample t test which indicates that there is a significant difference in the usability scores for bubble (M=7.0, SD=2.04) and hull (M=8.62, SD=1.33); t(13)=2.43, p=0.0305.
Is this the correct way to do it? My statistical knowledge is quite limited, but I think I should say if there was a significant difference or not.