B12.A particular bank is interested in estimating the difference between the average Mastercard debt at two of its branches. Using independent samples from two branches the 90% confidence interval for the difference between the means debt was calculated to be that-$5.43 1-?2

a)branch 2 customers have more average debt than customers from branch

b)branch 1 customers have more average debt than branch 2 customers.

c)the minimum average amount owed by branch 1 customers is $5.43.

d)there is no significant difference between the average debt at the two branches.

B13. A pilot study of 50 workers was conducted to provide information on the population standard deviation of wages in a particular industry. On the basis of this sample, 3 = $44 would be the estimate of 0. Determine the sample size required for estimating the mean weekly earnings with 98% confidence to within $4.50. a. 463 b. 519 C. 402 d. 520 B14. The average and standard deviation of weekly wages of equine workers were previously known to be $500 and $82 respectively. A sample of 63 was randomly selected and the average net weekly wage was found to be $523. The union wished to test whether average wages had increased since new working regulations were introduced. There was no reason to consider that the variation in wages had changed from that previously known. If the test was conducted using the 10% level of significance, the critical value of the test statistic would be a. 2.388 b. 1.28 0. 0.0398 d. 2.226