I have run a study on a group of 158 individuals to see if a teaching intervention can change their perceptions of scientists.
Before the intervention, all the children in the study were asked to choose 6 words to describe a scientist. This data collection was repeated at the end of a 5-week intervention, and then again 3 months after the intervention was complete.
I have begun processing the data and have categorised all the words that the children have used. When I look at the data for the cohort I can see that there has been a change in the types of words used to describe scientists (Pre 128 children used one stereotypical word, post this dropped to 67 and 64 in follow-up).
What statistical tests should I use to demonstrate the significance of these changes? All the data is tracked so I have individual data on the change of language use for each participant, I also have data for the group.