Question

5) (4.22) Thanksgiving spending, Part II. Exercise 4.14 provides a 95% confidence interval for the

average spending by American adults during the six-day period after Thanksgiving 2009: ($80.31, $89.11).

(a) A local news anchor claims that the average spending during this period in 2009 was $100.

What do you think of her claim?

(b) Would the news anchor’s claim be considered reasonable based on a 90% confidence interval? Why or why not? (Do not actually calculate the interval.)

Answer 1

From the given information ,

The 95% confidance interval (80.31,89.11)

a) The 95% confidant that the average spending during 2009 does not lie between the given interval. Hence, There is not sufficeint evidance to support the anchor claim.

b) No, Because lowering the confidance level the interval will more narrower that is 90% confidance interval is more narrower than 95%. Which also does not include average value.

hence it does not support the anchor claim