e-Text Exercises

e-Text Exercises

E-Text Exercises: Week 3
RES/342
September 17, 2011

E-Text Exercises: Week 3
10.29
Examine the data below showing the weights (in pounds) of randomly selected checked bags for
an airline's flights on the same day. (a) At ? = .05, is the mean weight of an international bag greater? Show the hypotheses, decision rule, and test statistic. (b) At ? = .05, is the variance greater for bags on an international flight? Show the hypotheses, decision rule, and test statistic.
Luggage
International (10 bags) Domestic (15 bags)
39 47                               29 37 43
54 48                               36 33 42
46 28                               33 29 32
39 54                               34 43 35
  69 2                               38 39 39

A) The interpretation of the hypotheses is that the null hypothesis is that the mean weight of the international bags is less than or equal to the mean weight of the domestic bags; and the alternative hypothesis is that the mean weight of the international bags are greater than the mean weight of the domestic bags.
The interpretation of the decision rule is that if the sample mean is close to the hypothesized mean then the null hypothesis that the mean weight of the international bags are less than or equal to the mean weight of the domestic bags would be accepted; and if the sample mean is far from the hypothesized mean then the null hypothesis would be rejected. Therefore, we would accept the null hypothesis if the sample mean is between 36.13 and 48.60, otherwise reject the null hypothesis.
The interpretation of the test statistic is that the sample estimates of the international and domestic bag weights are 3.163 from its expected value, in terms of its own standard error (Doane & Seward, pg. 352, 2007).
B) The interpretation of the hypotheses is that the null hypothesis is that the variance weight of the international bags is less than or equal to the variance weight of the domestic bags; and the...