I want to know how to perform a power analysis in the following case to know if my sample is good enough or not.
In my faculty, we have decided to apply a new lecturing methodology to a set of students, and we hypothesized that if we apply this methodology, then more than half of the students will have a drop in their marks.
However, we were only be able to test this methodology in a group of 30 students, because another classroom of approximately the same number of students was not able to follow this new methodology. We have also applied an h-test in our group, but we have received the critique that the sample size might be too small for such a text.
How to tackle this situation?