Unformatted text preview: GB 303 Fall 2011 Name: Quiz 7
(Chapter 10 covered) Use the following information for questions 1-3. A researcher suspects that sex discrimination is taking place at a local business. He examines the starting salaries of equally qualified men and women at the businesses and concludes that sex discrimination is taking place if the starting salary of men is significantly higher than the starting salary of women. Let m and w be the mean starting salaries for men and women respectively. You are given the following information: m=54000 w=53000 Sm=2000 Sw=1500 The sample consists of 50 men and 50 women. 1) State the null and alternative hypotheses. A) H0: m-w =0 H1: m-w 0 B) H0: m-w 0 H1: m-w <0 C) H0: m-w 0 H1: m-w >0 D) H0: m-w 0 H1: m-w =0 2) What is the test statistic for m-w? Assume the population variances are equal. A) 1.74 B) 2.33 C) 2.83 D) 14.29 3) Should the null hypothesis be rejected at =.05? At =.01? A) Yes, Yes B) Yes, No C) No, Yes D) No, No GB 303 Fall 2011 Name: Use the following information for questions 4-7. Ginkgo Biloba is an herbal supplement that supposedly enhances memory. To test its effectiveness you decide to conduct the following experiment. You give 4 people a memory test and record the number of errors made by each individual. Then, each participant takes Ginkgo Biloba for 30 days and retakes the memory test. Results are shown in the table below. Participant Errors Before Errors After Difference Judy 12 4 Joe 14 13 Josh 4 1 Jen 0 1 4) What is the point estimate for the population mean paired difference? A) 3.25 B) 2.75 C) 5.25 D) 0.25 5) What is the sample standard deviation for the difference? A) 44.75 B) 14.92 C) 3.86 D) 1.375 6) What is the test statistic? A) t = -1.424 B) t = -0.712 C) t = 0.712 D) t = 1.424 7) Was Ginkgo Biloba effective in reducing the number of errors on the memory test at the = 0.05 level? A) Yes, we rejected the null hypothesis of D = 0. B) Yes, we rejected the null hypothesis of D 0. C) No, we do not have enough evidence to reject the null hypothesis. D) No, we will accept the null hypothesis at the =0.05 level. 8) True or false? In testing for differences between the means of two related populations a paired t test should be used. A) True B) False GB 303 Fall 2011 Name: 9) True or false? The F distribution can take on positive or negative values. A) True B) False 10) True or False? If sample variances are only different by a multiple of 2 or 3, it is acceptable to assume equal population variances when performing a t test for independent samples with unknown population standard deviations. A) True B) False Answers: 1) C 2) C 3) A 4) B 5) C 6) D 7) C 8) A 9) B 10) A ...
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- Spring '08
- Statistics, Null hypothesis, researcher