Please answer all parts
2. (a. to g. 26 points) A courier service advertises that its average delivery time is less than 7.5 hours for local deliveries. A random sample of 8 deliveries to an address across town was recorded. These data are shown below (in hours). 8.21 5.98 4.25 5.48 4.78 7.35 6.45 2.95 7.23 4.92 Siudent’s Name (d) (10 points) Is there sufficient evidence at the 5% level of significance tical va to support Then apply the critical value lest the hypotheses. Make your conclusion in the context of the the courier’s advertisement? State the hypotheses. problem. (e) (2 points) Was it a z test or a f test in (d)? Briefly explain your answer. (f) (5 points) Provide a 95% confidence interval estimate for the courier’s average time for local deliveries. (g) (3 points) Can we conclude at the 95% level of confidence that the courier’s average time for local deliveries is less than 7.5 hours? Briefly explain your answer.