We're comparing the motivation reasons for different subgroups in this section.
We split the entire set of entries into two subsets and then apply Student's t-test
to find out if significant differences exist.
Confidence = 1 minus P-value
Motivation levels are converted to numbers by the following rules: "Weakly motivating" = 1 point, "Motivating" = 2 points, "Strongly motivating" = 3 points, "It discourages me" = -3 points.
Note that some responses are ignored to create the more significant gap between the two groups and to equalize the group sizes.