61. What is the sample mean of this data? If you use a 5% significance level would you conclude that the mean life of the light bulbs is typically more than 1500 hours? Explain your answer. 62. If you were to use a 1% significance level in this case would you conclude that the mean life of the light bulbs is typically more than 1500 hours? Explain your answer. QUESTIONS 63 AND 64 ARE BASED ON THE FOLLOWING INFORMATION: A study is performed in San Antonio to determine whether the average weekly grocery bill per five-person family in the town is significantly different from the national average. A random sample of 50 five-person families in San Antonio showed a mean of $133.474 and a standard deviation of $11.193. 63. Assume that the national average weekly grocery bill for a five-person family is $131. Is the sample evidence statistically significant? If so at what significance levels can you reject the null hypothesis? 64. For which values of the sample mean (i.e. average weekly grocery bill) would you decide to reject the null hypothesis at the .png”> significance level? For which values of the sample mean would you decide to reject the null hypothesis at the .png”> significance level? QUESTIONS 65 THROUGH 68 ARE BASED ON THE FOLLOWING INFORMATION: Do undergraduate business students who major in information systems (IS) earn on average higher annual starting salaries than their peers who major in marketing (Mktg)? Before addressing this question with a statistical hypothesis test a comparison should be done to determine whether the variances of annual starting salaries of the two types of majors are equal. Below you will find the StatPro output for 20 randomly selected IS majors and 20 randomly selected Mktg majors. Summary statistics for two samples IS Salary Mktg Salary Sample sizes 20 20 Sample means 30401.35 27715.85 Sample standard deviations 1937.52 2983.39 Test of difference .png”> 0 Sample mean difference 2685.5 Pooled standard deviation 2515.41 NA Std error of difference 795.44 795.44 Degrees of freedom 38 33 t-test statistic 3.376 3.376 p-value 0.0009 0.0009 Test of equality of variances Ratio of sample variances 2.371 p-value 0.034 65. Use the information above to perform the test of equal variance. Explain how the ratio of sample variances is calculated. What type of distribution is used to test for equal variances? Also would you conclude that the variances are equal or not? Explain your answer. 66. Based on your conclusion in Question 65 which test statistic should be used in performing a test for the existence of a difference between population means? 67. Using a 5% level of significance is there sufficient evidence to conclude that IS majors earn on average a higher annual starting salaries than their peers who major in Mktg? Explain your answer. 68. Using a 1% level of significance is there sufficient evidence to conclude that IS majors earn on average a higher annual starting salaries than their peers who major in Mktg? Explain your answer. 69. A recent study of educational levels of 1000 voters and their political party affiliations in a Midwestern state showed the results given in the table below. Use the 5% significance level and test to determine if party affiliation is independent of the educational level of the voters. Party Affiliation Democrat Republican Independent Didn’t Complete High School 95 80 115 290 Educational Level Has High School Diploma 135 85 105 325 Has College Degree 160 105 120 385 390 270 340 1000 QUESTIONS 70 THROUGH 73 ARE BASED ON THE FOLLOWING INFORMATION: A marketing research consultant hired by Coca-Cola is interested in determining if the proportion of customers who prefer Coke to other brands is over 50%. A random sample of 200 consumers was selected from the market under investigation 55% favored Coca-Cola over other brands. Additional information is presented below. Sample proportion 0.55 Standard error of sample proportion 0.03518 Z test statistic 1.4213 p-value 0.07761 70. If you were to conduct a hypothesis test to determine if greater than 50% of customers prefer Coca-Cola to other brands would you conduct a one-tail or a two-tail hypothesis test? Explain your answer.
