Chisquare for independence of attributes.
Can people really make out their favourite brand of cola? Volunteers tasted CocaCola Classic, Pepsi, Diet Coke, and Diet Pepsi, with the results shown below. Research problem: At _ = .05, is the correctness of the prediction different for the two types of cola drinkers? Could you recognize your favourite brand in this kind of test? Since it is a 2 _ 2 table, try also a twotailed twosample z test for ð1 = ð2 and confirm that z2 is the same as your chisquare statistic. Which test do you prefer? Why?
Correct?

Regular Cola

Diet Cola

Row Total

Yes, got it right

7

7

14

No, got it wrong

12

20

32

Column Total

19

27

46
