Business numbers

Test2verB_p3.xlsx

Prob 9

9. (16 pts) A local delivery service is assessing its delivery times by monitoring 5 randomly selected
delivery times each day over the past 12 days.
		Time (min)
	Day	Obs1	Obs2	Obs3	Obs4	Obs5	a. Calculate the process mean delivery time.
	1	26	12	25	12	23
	2	14	25	24	28	13
	3	22	27	12	29	27
	4	24	25	10	17	21
	5	24	28	27	30	29
	6	18	10	12	30	11	b. If the process standard deviation is 5.6 min, calculate
	7	12	27	19	15	29	the 3-SEM upper and lower lower control limits on delivery time.
	8	17	24	16	14	19
	9	16	17	20	14	30
	10	23	18	21	15	24
	11	16	18	20	19	11
	12	27	12	23	23	18

10. (14 pts) A random sample of 45 cases from a personal injury lawyer advertising on TV has a mean monetary

award of $235,000 with a standard deviation of $62,500. Construct a 95% confidence interval for the true

mean award value.