1) A personnel manager is conducting a study of sales supervisory salaries in this industry. A survey for the salaries of 36 sales supervisors found a mean of $42.91 thousand and a standard deviation of $19.22 thousand. Determine a 98-percent confidence interval (in thousands of dollars) for the mean of all sales supervisory salaries in this industry. (Round your answer(s) to 3 decimal places.)
98% CI =__________ to_______________
2) Raising in-state and out-of-state tuition is supposed to reduce the number of students in state supported universities. The registrar of a university wants to estimate the proportion, ? , of students who are paying out-of-state tuition on the installment plan (to later be compared with in-state installment plan payers). A random sample of 70 students who live out-of-state is taken and 38 of them pay tuition on the installment plan. Find a 99-percent confidence interval for ? based on these data. (Round your answer(s) to 3 decimal places.)
99% CI = __________ to _____________
3) Population assumption: Normal
n = 16; x = 84; s = 13;
H0: u ??? 84, H1: u > 84; a = 0.01
What test do you use and what is the test statistic? (Round your answer(s) to 3 decimal places.)
t-testz or z-test
Test statistic =___________(3 decimal places)