Section A: Short Answer Questions and Fill in the BlankQuestions (60 points). 1. A study by a bank compared the averagesavings of customers who were depositors for three years or lesswith those who had been depositors for more than three years. Theresults of a sample are: Assuming that the financial officer wantsto show that there is a difference in the average savings balancebetween the two classes of depositors what is the null hypothesis?_____________________ 2. If we are testing for the differencebetween two population means and assume that the two populationshave equal but unknown standard deviations then the test has_________ degrees of freedom. 3. The pooled estimate of theproportion is found by dividing the total number of successes by__________________________. 4. If we are testing for the differencebetween two population means and assume that the two populationshave equal and unknown standard deviations the standard deviationsare _____. 5. When independent samples with unknown but equalstandard deviations are used to test for differences in the meanswe pool the sample ________________. 6. The paired t test isespecially appropriate when the sample sizes of two groups are_______. 7. The paired difference test has ___________ degrees offreedom. 8. When testing the difference between two populationmeans the hypothesized difference is _______________. 9. Whentesting the difference between two population proportions thehypothesized difference is _______________. 10. A statisticsprofessor wants to compare grades in two different classes of thesame course. This is an example of _________ populations. SectionB: Hypothesis Testing (40 points). 11. A financial planner wants tocompare the yield of income and growth mutual funds. Fifty thousanddollars is invested in each of a sample of 35 income and 40 growthfunds. The mean increase for a two-year period for the income fundsis $900. For the growth funds the mean increase is $875. Incomefunds have a sample standard deviation of $35; growth funds have asample standard deviation of $45. Assume that the populationstandard deviations are equal. At the 0.05 significance level isthere a difference in the mean yields of the two funds? Whatdecision is made about the null hypothesis using and a = 0.05?____________ 12. A company is researching the effectiveness of anew web site design to decrease the time to access a website. Fiveweb site users were randomly selected and their times (in seconds)to access the web site with the old and new designs were recorded.The results follow.
Written on May 6th, 2018 by
Section A: Short Answer Questions and Fill in the BlankQuestions (60 points). 1.
Posted in Uncategorized