I have a rating (from 1 to 5) under two conditions (let’s call them "blue" and "red"). I tested whether the distribution of the ratings is significantly different using a chi squared test for goodness of fit. The test results were null - meaning I could not say that the rating distribution of the blue and red groups is significantly different.
Would looking at only a partial sub-group of the data be considered a legitimate calculation?
Example: asking whether the distribution of blue and red is different only for the “1” and “5” ratings (without the rating 2-3-4).
- If yes: What can I test further?
- If no: What is the problem with such an examination?