Instructions: In all exercises, include MegaStat, Excel, or MINITAB exhibits to support your calculations. 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
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
The expert uses chi square tests to predict identification of two types of cola drinkers for regular and diet.