Question

Problem 7. (10 points) Collette is self-employed, selling cosmetics at home parties. She wants to estimate the average amount a client spends per year at these parties. A random sample of 16 receipts had a mean of *$340.70 with a standard deviation of s = $60.15. Find a 90% confidence interval for the mean amount u spent by wi clents. Assume x has a distribution that is approximately normal a. What is the critical value of the variable for the pven confidence lever b. What is the maximal margin of errors C. The lower endpoint of the 90% confidence interval for is d. The upper endpoint of the 90% confidence interval iss • round your answers to the nearest hundredth Note: You can earn partial credit on this problem preview answers

Answer 1

ANSWER:

Given that n= 16 ña $340 70 S = $60.15 90 % CI for rean u since has distbh that is appronimately normal @ the critical value of the t variable for the given confidence level trite for 2 = 10 % (for 2 taul) at (16-1) df 1.753 2 from table b НАЛ error (omantinal argin of I dla fin 1.753 X 60.15 16 1.7534 60.15 Scanned with CamScanner 4

92-94 @ lower and paint of 90 40 CI g. error (margin of error и Бhs-hs the upper end point of 90% CI ноча *n of vod $ Ҳчо - 76 +26: 36 $ 367. о.,