I have been struggling with this question all day, reading everything I could find, but still do not have a clear answer.
A part of my research was that: 30 students tried a new educational instrument (virtual patient). Before the interaction with the patient they filled in 18 Likert items, from 1 to 5 (1=highly disagree, 5=highly agree) about their expectations about the instrument, i.e. "I am going to be deeply concentrated during the exercise". After the exercise, they filled in 18 similar Likert items, again from 1 to 5, about the actual experience, i.e. "During the exercise, i was deeply concentrated".
An interesting aspect for me, is to examine weather there is a significant difference between the answers before and after the exercise, looking at each likert item separately.
What test should I use? If I get it right, t-test would not be the case here. Or am I wrong? What about Wilcoxon signed rank-test? Should I present and compare means or medians?
As you can probably understand I am by no means an expert in statistics, and I appreciate deeply any kind of help.