As a side project to my thesis, I was interested in analyzing learning trends in my sample. In sum, I had two groups of participants (controls vs. adults diagnosed with ADHD, the latter whom completed the trials both on and off stimulant medication) write the word "hello" in cursive and a novel symbol 30 times each on a digitizing tablet. Specialized software then breaks down the handwriting signals into measures of fluency (i.e., normalized jerk [NJ]). The higher the NJ, the more dysfluent the handwriting signal, the lower the NJ score, the more fluent and automated the handwriting signal. What I found when plotting the novel symbol NJ data across 30 trials were some visually salient differences between the groups and within the groups. To this point, however, I have not learned how to conduct statistical analyses of trends. What statistical analyses are particularly powerful and elegant to conduct these types of analyses? That is, analyses of learning over repeated trials. Please let me know if additional information or context is necessary to help answer this question.