WiFi Only 3G/4G+WiFi 12.40 10.60 11.50 12.60 8.00 10.90 11.60 10.00 10.90 8.90 9.50 10.50 11.70 11.40 10.70 11.50 11.30 11.60 8.90 An important feature of tablets is battery life, the number of hours before the battery needs to be recharged. The file Tablets contains the battery life of 12 WiFi-only and 7 3G/4G/WiFi 9- through 12-inch tablets. a. Assuming that the population variances from both types of tablets are equal, is there evidence of a difference in the mean battery life between the two types of tablets? 1Use a = 0.05.2 b. Determine the p-value in (a) and interpret its meaning. c. Assuming that the population variances from both types of tablets are equal, construct and interpret a 95% confidence interval estimate of the difference between the population mean battery life of the two types of tablets. the number arged. The file Tablets 7 3G/4G/WiFi om both types of ? 1Use a = 0.05.2 its meaning. om both types of lation mean Separate-Variances t Test (assumes equal population variances) Data Hypothesized Difference Level of Significance Population 1 Sample Sample Size Sample Mean Sample Standard Deviation Population 2 Sample Sample Size Sample Mean Sample Standard Deviation Intermediate Calculations Population 1 Sample Degrees of Freedom Population 2 Sample Degrees of Freedom Total Degrees of Freedom Pooled Variance Standard Error Difference in Sample Means t Test Statistic Two-Tail Test Lower Critical Value Upper Critical Value p-Value Do not reject the null hypothesis Separate-Variances t Test (assumes unequal population variances) Data Hypothesized Difference Level of Significance Population 1 Sample Sample Size Sample Mean Sample Standard Deviation Population 2 Sample Sample Size Sample Mean Sample Standard Deviation 0 0.05 22 25535.4090909091 17082.1003 15 32954.7333333333 29358.9533 21.0000 14.0000 35.0000 519858146.3500 7634.6005 4.3165 0.0006 -2.0301 2.0301 0.9996 0 0.05 22 25535.4090909091 17082.1003 15 32954.7333333333 29358.9533 Intermediate Calculations Pop. 1 sample variance 291798150.729437 Pop. 2 sample variance 861948139.78095 Pop. 1 Sample var./sample size 13263552.3059 Pop. 2 Sample var./sample size 57463209.3187 Numerator of Degrees of Freedom 5002274809904930.0000 Denominator of Degrees of Freedom 244235831313486.0000 Total Degrees of Freedom 20.4813 79197 54262 42101 42101 39497 34430 27051 25008 22620 21001 19950 19072 18235 17341 14926 14177 12637 12356 11743 11663 11351 11060 107541 90185 53615 36390 35740 29768 20913 19469 18105 16800 14174 13837 13710 12407 11667 Degrees of Freedom Separate Variance Denominator Difference in sample means t Test Statistic 20.0000 8409.9204 -7419.3242 -0.8822 Two-Tail Test Lower Critical Value -2.0860 Upper Critical Value 2.0860 p-Value 0.388143195827309 Do not reject the null hypothesis Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Financial Institutions Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology Technology What motivates employees? The Great Place to Work Institute evaluated nonfinancial factors both globally and in the United States. a. At the 0.05 level of significance, is there evidence of a difference in the mean rating between global and U.S. employees? b. What assumption is necessary about the population distribution in order to perform this test? c. Use a graphical method to evaluate the validity of the assumption in (b). Factor Being treated with respect Work/life balance The type of work that you do The quality of the people you work with The quality of the leadership of the organization Base pay Working in an environment where you can provide good service to others Long-term career potential Having flexible working arrangements Learning and development opportunities Benefits Promotion opportunities Incentive pay/bonus data Global U.S. 119 111 110 107 107 106 104 92 91 90 90 89 84 123 112 111 111 112 104 112 91 91 81 106 77 71 F Test for Difference in Two Variances Data Level of Significance Larger-Variance Sample Sample Size Sample Variance Smaller-Variance Sample Sample Size Sample Variance 0.05 0 Err:504 0 Err:504 Intermediate Calculations F Test Statistic Population 1 Sample Degrees of Freedom Population 2 Sample Degrees of Freedom #DIV/0! -1 -1 Two Tailed Test Upper Critical Value P-value Err:502 #DIV/0! #DIV/0! Region Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Southeast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Thereis insufficient evidence to conclude that the two population variances are Gulf Coast different. The test assumes that each of the two Gulf Coast populations is normally distributed. (d) Based on (a) and (b), a pooledvariance t test should be used. Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast Gulf Coast A problem with a telephone line th from receiving or making calls is up and the telecommunications comp samples of 20 problems reported t company and the time to clear the minutes) from the customers' line a. At the 0.05 level of significance, in the variability of the time to cle two central offices? b. Determine the p-value in (a) and c. What assumption do you need t populations in order to justify your d. Based on the results of (a) and ( 10.1 should you use to compare th problems in the two central offices m with a telephone line that prevents a customer iving or making calls is upsetting to both the customer elecommunications company. The file Phone contains f 20 problems reported to two different offices of a telecommunications and the time to clear these problems (in rom the customers' lines. 0.05 level of significance, is there evidence of a difference ability of the time to clear problems between the ine the p-value in (a) and interpret its meaning. ssumption do you need to make in (a) about the two ns in order to justify your use of the F test? on the results of (a) and (b), which t test defined in Section ld you use to compare the mean time to clear in the two central offices? Time Location 1.48 1 1.75 1 0.78 1 2.85 1 0.52 1 1.60 1 4.15 1 3.97 1 1.48 1 3.10 1 1.02 1 0.53 1 0.93 1 1.60 1 0.80 1 1.05 1 6.32 1 3.93 1 5.45 1 0.97 1 7.55 2 3.75 2 0.10 2 1.10 0.60 0.52 3.30 2.10 0.58 4.02 3.75 0.65 1.92 0.60 1.53 4.23 0.08 1.48 1.65 0.72 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2