COURSE: DSCI 3710 Print Name: KEY Exam 2 – version A Signature: Fall 2010 Student ID#: INSTRUCTIONS: - Please print your name and student ID number on this exam. Also, put your signature on this exam. - On your scantron PRINT your name and exam version. To better protect your privacy also print your name on the backside of your scantron. - You have 120 minutes to complete this exam. The exam is open book, open notes, and open mind. You may use any type of hand calculator but please show all your work on the exam and mark all answers on the scantron. Usage of cell phones, digital cameras, PDAs, and other communication devices is strictly prohibited. - Many of the questions follow the format of those in Hawkes Learning Systems Business Statistics. The remaining questions are either based on the Excel assignments or use an HLSBS-like approach with problems nearly identical to those assigned in the textbook. - Please DO NOT pull this exam apart. When you have completed the exam, please turn in your scantron and exam booklet to your instructor, at the front desk. - No cheating. - Good luck and we wish you well on the exam. Note: Whenever question(s) are connected you may be asked to assume a result (given a value) as an answer for the previous question but this result (value) may or may not be correct. The procedure is set in place to prevent you from losing points on a subsequent question because you made a mistake on some previous question/s.Use the information given below to answer the next 6 questions. In studying his campaign plans, Mr. Singleton wishes to better understand men's and women's views regarding his appeal as a candidate. He asks his campaign manager to take two random independent samples. A random sample of 654 male (m) voters and 709 female (f) voters was taken. 267 men and 314 women favored Mr. Singleton as a candidate. Is there evidence that a significantly larger proportion of women favor Mr. Singleton as a candidate as compared to men? Use a 0.05 level of significance. 1. What are the null hypothesis and alternative hypothesis for this test? A. Ho: pm = pf Ha: pm … pf B. Ho: Fm < Ff Ha: Fm > Ff C. Ho: pm < pf Ha: pm > pf D. Ho: pm > pf Ha: pm < pf * E. Ho: Fm = Ff Ha: Fm … Ff 2. Where is the Reject Ho region for testing the relative preference of Mr. Singleton by men versus women as stated in the above case? A. Z > 1.282 B. Z < ─ 1.645* C. Z > ─ 1.282 D. Z > 1.96 E. Z < ─ 2.33 3. Assuming the p-value (observed level significance) is 0.13, what are the decision and conclusion of the test of hypothesis at the 5% level of significance? A. Fail to reject the null hypothesis, conclude there is sufficient evidence that women prefer Mr. Singleton’s candidacy more than men. B. Reject the null hypothesis, conclude there is sufficient evidence that women prefer Mr. Singleton’s candidacy more than men. C. Fail to reject the null hypothesis, conclude there is insufficient evidence that women prefer Mr. Singleton’s candidacy more than men.* D. Reject the null hypothesis, conclude there is no evidence that women prefer Mr. Singleton’s candidacy more than men. E. Reject the null hypothesis, conclude there is insufficient evidence that women prefer Mr. Singleton’s candidacy the same as men.4. Assuming the calculated value of the test statistic is -3.25, what are the decision and conclusion of the test at the significance level of 0.05? A. Fail to reject the null hypothesis, conclude there is sufficient evidence that women prefer Mr. Singleton’s candidacy more than men. B. Reject the null hypothesis, conclude there is sufficient evidence that women prefer Mr. Singleton’s candidacy more than men.* C. Fail to reject the null hypothesis, conclude there is insufficient evidence that women prefer Mr. Singleton’s candidacy more than men. D. Reject the null hypothesis, conclude there is no evidence that women prefer Mr. Singleton’s candidacy more than men. E. Reject the null hypothesis, conclude there is insufficient evidence that women prefer Mr. Singleton’s candidacy the same as men. 5. Suppose the value of the calculated test statistic is ─1.96. Which one of the following would best describe the p-value of the test? A. 0.1 B. 0.05 C. 0.025* D. 0.074 E. 0.037 6. What is the pooled proportion of men and women favoring Mr. Singleton’s candidacy? A. 0.574 B. 0.632 C. 0.451 D. 0.185 E. 0.426* Use the information given below to answer the next 3 questions. American restaurants have become very creative in serving tacos. Sixty judges (20 for each of the three types of tacos) rated three taco dishes (a higher rating is better). Is there sufficient evidence that the mean ratings differ? Use a 5% significance level. Use Tukey's multiple comparison procedure at the 5% significance level to determine which mean ratings differ. FishTaco: Rating for taco made with fish ShrimpTaco: Rating for taco made with shrimp CalamariTaco: Rating for taco made with calamariAnova: Single Factor SUMMARY Groups Count Sum Average Variance FishTaco 20 149.600 7.480 1.596 ShrimpTaco 20 142.800 7.140 0.577 CalamariTaco 20 129.200 6.460 1.815 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 10.789 2.000 5.395 4.057 0.023 xxxx Within Groups 75.788 57.000 1.330 Total 86.577 59.000 TUKEY MULTIPLE COMPARISON TEST Critical Q Distance Alpha 3.4 0.877 0.05 Means joined by a double line are not significantly different. CalamariTaco ShrimpTaco FishTaco 6.460 7.140 7.480 7. What (approximately) is the critical (table) value of the test statistic at the 5% significance level to test the null hypothesis that the three taco dishes have the same mean ratings? A. 4.057 B. 5.395 C. 3.159* D. 2.393 E. 3.4 8. What is the conclusion of testing the null hypothesis that the three taco dishes have the same mean ratings at the 1% significance level? A. Reject the null hypothesis B. Reject the alternative hypothesis C. Fail to reject the alternative hypothesis D. Fail to reject the null hypothesis* E. Accept the null hypothesis9. Simply based
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