Provide an appropriate response.

Seven randomly selected plants that bottle the same beverage implemented a time management program in hopes of improving productivity. The average time, in minutes, that it took the companies to produce the same quantity of bottles before and after the program are listed below. Assume the two population distributions are normal. Construct a 90% confidence interval for the mean difference. Assume that the paired data came from a population that is normally distributed.

A) (-22, 33.3) B) (-0.22, 11.36) C) (0.21, 10.93) D) (1.60, 9.54)

5. Provide an appropriate response.

A weight-lifting coach claims that weight-lifters can increase their strength by taking a certain supplement. To test the theory, the coach randomly selects 9 athletes and gives them a strength test using a bench press. The results are listed below. Thirty days later, after regular training using the supplement, they are tested again. The new results are listed below. Test the claim that the supplement is effective in increasing the athletes’ strength, on average. Use ? = 0.01. State the conclusion. Assume that the distribution is normally distributed.

A) We can reject the null hypothesis at the 1% level of significance. B) There is insufficient evidence to suggest that the supplement is not effective in increasing the athletes’ strength, on average. C) There is sufficient evidence to suggest that the supplement is effective in increasing the athletes’ strength, on average. D) There is insufficient evidence to suggest that the supplement is effective in increasing the athletes’ strength, on average. 6. Provide an appropriate response.

In a recent survey of gun control laws, a random sample of 1000 women showed that 65% were in favor of stricter gun control laws. In a random sample of 1000 men, 60% favored stricter gun control laws. Construct a 95% confidence interval for p1 p2. A) (0.008, 0.092) B) (-1.423, 1.432) C) (0.587, 0.912) D) (-2.153, 1.679) 7. Provide an appropriate response.

A study was conducted to determine if the salaries of elementary school teachers from two neighboring districts were different. A sample of 60 teachers from each district was randomly selected. The mean from the first district was $28,900 with a pop. standard deviation of $2000. The mean from the second district was $30,300 with a pop. standard deviation of $2990. (Assume the variances are not equal.) Construct a 95% confidence interval for ?1 – ?2.

A) (-4081, 597) B) (-2054, 238) C) (-2310, -489.8) D) (-2789, -10.82) 8. Provide an appropriate response.

A study was conducted to determine if the salaries of firefighters from two neighboring cities were different. A sample of 75 firefighters from each city was randomly selected. The mean from the first city was $38,200 with a population standard deviation of $3100. The mean from the second city was $40,150 with a population standard deviation of $3300. Construct a 99% confidence interval for ?1 – ?2. A) (-3297, -603) B) (-2871, 567) C) (-4081, 597) D) (-2054, 238)

10. Provide an appropriate response.

At a local college, 65 female students were randomly selected and it was found that their mean monthly income was $609 with a population standard deviation of $121.50. Seventy-five male students were also randomly selected and their mean monthly income was found to be $651 with a population standard deviation of $168.70. Test the claim that male students have a higher mean monthly income than female students. Use ? = 0.01. State the conclusion. A) There is insufficient evidence to suggest that male students have a higher mean monthly income than female students. B) There is sufficient evidence to suggest that male students have a higher mean monthly income than female students. C) There is sufficient evidence to suggest that female students have a higher mean monthly income than male students. D) We are 1% confident that male students have a higher mean monthly income than female students.