Can people really recognize their favorite brand of cola? Volunteers tasted Coca-Cola Classic, Pepsi, Diet Coke, and Diet Pepsi, with results shown below.
Research problem: At α = .05, is correctness of the prediction different for the two kinds of cola drinkers?
Could you recognize your favorite brand in this kind of test?
Since it is a 2 × 2 table, try as well a two-tailed two-sample z test for π1 = π2 and verify that z2 is the same as your chi-square statistic. Which test do you prefer? Why?
|Yes, got it right
|No, got it wrong