Solve the following:
State the hypotheses, show how the degrees of freedom are calculated, find the critical value of chisquare from Excel's function =CHIINV(alpha, deg_freedom), and interpret the p-value.
Tell whether the conclusion is sensitive to the level of significance chosen, identify cells that contribute the most to the chi-square test statistic, and check for small expected frequencies. If necessary, you can calculate the p-value by using Excel's function =CHIDIST(test statistic,deg_freedom
Q: Can people really identify their favorite brand of cola? Volunteers tasted Coca-Cola Classic, Pepsi, Diet Coke, and Diet Pepsi, with the results shown below.
Research question: At α = .05, is the correctness of the prediction different for the two types of cola drinkers? Could you identify your favorite brand in this kind of test?
Since it is a 2 × 2 table, try also 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?
Correct? Regular Cola Diet Cola Row Total
Yes, got it right 7 7 14
No, got it wrong 12 20 32
Col Total 19 27 46