Our second test was to confirm that modifiers did not affect flee rates. Since our sample was limited to only Pokemon that broke out of the ball, it is possible that there is a bias due to fewer low level Pokemon being in the sample. This is because high level Pokemon have lower catch rates and thus, would be more likely to break out of a ball. To address this bias in the previous binomial test, we wanted to make sure that level had no impact on flee rates before continuing on to other modifiers.

First, we split the sample into groups based on base catch rate and base flee rate. For example, one group consisted of encounters with Bulbasaur, Charmander, Pikachu and Squirtle, which all have base flee rate = 0.1 and base capture rate = 0.16. We then ran a logistic regression for each group to see if level is related to likelihood of fleeing when keeping the other modifiers (berries, throw bonuses, curveballs, ball type) constant. This type of regression is used to see if the independent variable (in our case, level) has a statistically significant effect on the likelihood of the dependent variable (in our case, fleeing). For all of our regressions, level had no statistical effect on flee rate.

To make sure that no other modifiers affected the flee rate, we ran logistic regression again for each group using the modifiers as independent variables. None of the modifiers were statistically significant, so we concluded that ball type, throw bonuses, level, curve, and berries have no effect on flee rates. This leads us to conclude that flee rates of Pokemon are based on their base flee rate alone.