Chi-Square Test for Independence
In addition to the goodness-of-fit test, the chi-square distribution can also test for independence between variables. To demonstrate this technique, I’m going to revisit the tennis example from Chapter 7.
If you recall, Debbie felt that a short warm-up period before playing our match was hurting her chances of beating me. After examining the conditional probabilities, I had to admit there was some evidence supporting Debbie’s claim. However, I’m not one to take this sitting down. I demand justice, I demand further evidence, I demand a recount. (Oh, wait a minute, this isn’t Florida.) I demand … a hypothesis test using the chi-square distribution!
Unbeknownst to Debbie, I have meticulously collected ...