Can people really identify their favorite brand of cola?Volunteers tasted Coca-C
ID: 2916624 • Letter: C
Question
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 = .05,is
the correctness of the prediction different for the two types ofcola 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 1 = 2 (see Chapter10) and verify that z2 is the same as your chi-squarestatistic.Which
test do you prefer? Why? (Data are from ConsumerReports 56, no. 8 [August 1991], p. 519.)
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
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
Explanation / Answer
Research question: At = .05, is the correctness of theprediction different for the two types of cola drinkers?Could you identify your favorite brand in this kind of test?
Chi-Square Test:
Ho: Cola type and quessing results are homogeneous (the same forboth Colas)
Ha: Results are not homogeneous
Ran a Chi-Square on the 2 x 2 with the following results:
Test statistic: 0.62768...
p-value: 0.428...
Conclusion: Since the p-value is greater than 5%, fail to rejectHo.
Results are the same for both solas.
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Since it is a 2 × 2 table, try also a two-tailed two-sample ztest for 1 = 2 (see Chapter 10) and verify that z^2 isthe same as your chi-square statistic.
Which test do you prefer? Why? (Data are from Consumer Reports 56,no. 8 [August 1991], p. 519.)
---------------------------------------
Ran a 2-sample z-Test:
Ho: u1=u2
Ha: u1 is not equal to u2
--------------------
test statistic: z = -0.72428596...
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Does z^2 = the Chi-Sq
(-0.72428596..)^2 ? 0.62768...
Not quite. Hope this helps~ Please Rate!