Hello, I'm doing a statistics project for college but I came across a few questions. I'm making an experiment with a sample of 21 students. I'm comparing the reading time between reading on traditional white paper and reading on light blue colored paper. Each student was tested under both conditions (both papers had similar length and difficulty passages). I'm not pasting the whole exercise because I want to solve it on my own, but I'm having a few doubts. I'm asked to first make a descriptive analysis and then an inferential one. For the descriptive analysis, The first thing I did was a bar graph showing each student with both scores (W and LB papers). That's Ok, by a visual analysis I can say that it's evident that most students were quicker on X type of paper, except for one possible outlier. But then I'm asked to test for normality and what I try to make is a Frecuency Polygon by "mixing" the scores in groups of tens, since the sample is so small, the Frecuency polygon turned out very weirdly at first . Then I can see both curves are slightly skewed, but I don't know how to actually calculate normality, nor outliers.

Also, I'm confused whether I should calculate the mean, median, mode, variance and standard deviation for each set of types of papers or it'd be more suitable to calculate the difference between each score for each student and then calculate these values.

I would greatly appreciate if you could help me how to approach to the exercise and also interpretate the information