Question

Need Help with Quick Check 10.3.2
CHAPTER 10: INFERENCES FOR TWO POPULATIONS 1 481 rthermore, the hypothesis that the mean balances are equal is rejected at the 5% level of significance. Tis conforms to the results suggested by the confidence interval. Assume equal population variances for these problems. quick Check 10.3.1: In 2014 the state of California raised the minimum wage from 59 per hour. Concern arose as to the effect this would have on increase, a sample of 18 small retail establishments reported a mean level of employment of 12.5 employees, with a standard deviation of 3.6. After the increase, a random sample of 10 businesses revealed a mean of 8.6 employees, with a standard deviation of 5.6. Construct a 95% confidence interval for the difference in the mean number of employees. Report the results of a hypothesis test for equal means with a 5% level of significance. $8 per hour to employment levels. Before the Ans: 0.3357 to 7.46; t-test 2.249 >2.0555, reject null Quick Check 10.3.2: Prior to changing the type of raw material used to produce its product, a manufacturer suffered a monthly mean number of defects of 3.2, with a standard deviation of 0.73. After the change, the mean number of defects rose to 4.7 per month, with a standard deviation of 0.92. A total of 18 months were used for the first sample and 9 months for the sample after the change. Do these results suggest the manufacturer should switch back to the original material? Respond with a 99% confidence interval and a hypothesis test at the 1% level of significance. Ans: -2.406 to -0.594; -4.6174 <-2.787, reject null. Appears defect rate rose-return to original material Quick Check 10.3.3: Purchases averaged $123 with a standard deviation of $67.10 for 16 weekdays. An average for 10 Saturdays was found to be S147, with a standard deviation of S58.20. Use a 90% confidence interval and a hypothesis test with an alpha value of 10% to compare sales. 1.7108; do not reject Ans: -60.08 to 20.08; t-test -0.931 between t SECTION 10.3 PROBLEMS Conceptual Problems 1. How do you interpret a confidence interval for the difference between the two means if both the lower bound and the upper bound are negative? 2. How do you interpret a confidence interval for the difference between two means if both the lower bound and the upper bound are positive? 9. How do you interpret a confidence interval for the difference betwen two means if he lower bound s negative and the upper bound is positive?

Answers are under the Questions, but need to show work to see how they're solved. Help is appreciated

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