Question

As part of a project for their Intro Stat course, two students compared two brands of chips, Frito Lays and Golden Flakes, to see which company gives you more for your money. Five bags of each brand (which, according to the label, each contained 35.4 grams) were measured with a very accurate scale. Use the Wilcoxon Rank-Sum test to see if there are any significant differences between the two brands in the amount of product they put in their bags.
Frito Lays: 35.3 35.4 35.8 35.9 35.9
Golden Flake: 35.3 37.8 38.8 38.1 42.5 8.
1. The null hypothesis is about:
(a) the mean contents of the bags for Frito Lays and Golden Flakes brands
(b) the mode of the contents of the bags for Frito Lays and Golden Flakes brands
(c) the distribution of the contents of the bags for the two brands
(d) the number of bags with contents below the label weight for the two brands 9.

2. The alternative hypothesis, according to the problem stated above, is that:
(a) Frito Lays gives you more chips than Golden Flakes
(b) Frito Lays gives you less chips than Golden Flakes
(c) Frito Lays gives you either more or less chips than Golden Flakes
(d) Golden Flakes gives you more chips than the amount stated on the label 10.

3. The bags that contained 35.9 grams will receive a rank of:
(a) 4
(b) 4.5
(c) 5
(d) 5.5

4. The p-value for the test was 0.1164. We conclude that:
(a) Frito Lays gives you more chips.
(b) Golden Flakes gives you more chips.
(c) There is not enough evidence to prove a difference between the two brands.
(d) There is enough evidence to prove a difference between the two brands

5. If the assumptions for the Normal based procedure were satisfied, we could analyze the data with a confidence interval for:
12
(a) μ
(b) μ1-μ2
(c) μd
d) η1- η 2

6. Why is it not a good idea to use the Normal-based procedure here?
(a) the data was not randomly selected
(b) the data does not have a continuous distribution
(c) the outlier violates the assumption of Normality
(d) the nonparametric method is always better

7. Which of the following kinds of data should be analyzed with non-parametric procedures?
(a) normal
(b) continuous
(c) ranks
(d) all of the above

8. Given that all the necessary assumptions for each test are satisfied, which are more powerful at finding significant differences?
(a) Nonparametric procedures, since their assumptions are generally easier to satisfy.
(b) Normal-based procedures, since they take into consideration the shape of the distribution.
(c) Nonparametric procedures, since their assumptions are generally harder to satisfy.
(d) Normal-based procedures, since they work for distributions of almost any shape.

Answer 1

1. The null hypothesis is about:
(a) the mean contents of the bags for Frito Lays and Golden Flakes brands

2. The alternative hypothesis, according to the problem stated above, is that:
(c) Frito Lays gives you either more or less chips than Golden Flakes

3]

The bags that contained 35.9 grams will receive a rank of 5.5

4] There is not enough evidence to prove a difference between the two brands.

5] (b) μ1-μ2

6] c) the outlier violates the assumption of Normality

7] ALL ABOVE

8] (b) Normal-based procedures, since they take into consideration the shape of the distribution.