Carol and Yu-Han!
AP Statistics:
The Ultimate Beverage Buying Guide
Description:
 Objective: to investigate whether or not students can taste the difference between
Sprite and 7-Up
 Population: PHS students
 Sample size: 47 students from 8th period AP stat, AP comp sci, and Acc geometry
classes
 Null Hypothesis: students cannot taste any difference between the two sodas
 Alternate Hypothesis: students can distinguish between the two sodas
Procedure:
 Prepare area by blindly putting each bottle into a brown bag and labeling each bag
A and B (neither the testers nor the subjects know which soda is in which bag)
 Call up each student in the class in order
 Have the student flip a coin to randomly determine which bagged soda he or she
tastes first
 Pour a small amount into a plastic cup and have the student drink it all
 Do the same for the other soda
 Ask the student to write down which is Sprite and which is 7-Up
Results:
Results of the test
Correct
Observed
Expected
Observed
Expected
Incorrect
25
23.5
Total
22
23.5
Percentages
Correct
Incorrect
53.19%
46.81%
50%
50%
Chi Square Test
χ2-value
P-value
df
47
47
Total
100%
100%
0.1915
0.3383
1
Observed vs Expected
100.00%
90.00%
80.00%
Percent
70.00%
60.00%
Incorrect
Correct
50.00%
40.00%
30.00%
20.00%
10.00%
0.00%
Observed
Expected
Analysis and Conclusion:
 As seen on the segmented bar graph, the observed results are close to the expected
even distribution. A few more students could taste the difference between Sprite
and 7-Up.
 We carried out a chi square test of homogeneity with one degree of freedom; we
got a chi square value of 0.1915. The p-value is 0.3383.
 Since the p-value is big (greater than a confidence level of α=0.05), the test does
not give statistically significant evidence to reject the null hypothesis; in other
words, there is not sufficient evidence to assume that PHS students can taste the
difference between Sprite and 7-Up.
 Possible sources of error:
o Convenience sampling—though we sampled everyone in the three classes,
the classes we did sample were not picked randomly
o The subjects used the same cup for both drinks (this could have resulted in
contamination of the second drink—we tried to minimize this effect by
randomizing the order we served the drinks by flipping a coin).
Real World Application:
 If you plan to have a party with PHS students, it doesn’t matter whether or not
you serve Sprite or 7-Up. During the test, even many test subjects who felt
confident that they could tell the difference between the two drinks ended up
confusing the two.