Confidence Interval

27. A recent study focused on the number of times men and women who live alone buy
take-out dinner in a month. The information is summarized below.
At the .01 significance level, is there a difference in the mean number of times men and
women order take-out dinners in a month? What is the p-value?

Statistic Men Women
Sample mean 24.51 22.69
Population standard
deviation 4.48 3.86
Sample size 35 40

46. Grand Strand Family Medical Center is specifically set up to treat minor medical emergencies
for visitors to the Myrtle Beach area. There are two facilities, one in the Little
River Area and the other in Murrells Inlet. The Quality Assurance Department wishes to
compare the mean waiting time for patients at the two locations. Samples of the waiting
times, reported in minutes, follow:

Assume the population standard deviations are not the same. At the .05 significance level,
is there a difference in the mean waiting time?

Location Waiting Time
Little River 31.73 28.77 29.53 22.08 29.47 18.60 32.94 25.18 29.82 26.49
Murrells Inlet 22.93 23.92 26.92 27.20 26.44 25.62 30.61 29.44 23.09 23.10 26.69 22.31

23. A real estate agent in the coastal area of Georgia wants to compare the variation in the
selling price of homes on the oceanfront with those one to three blocks from the ocean.
A sample of 21 oceanfront homes sold within the last year revealed the standard deviation
of the selling prices was $45,600. A sample of 18 homes, also sold within the last
year, that were one to three blocks from the ocean revealed that the standard deviation
was $21,330. At the .01 significance level, can we conclude that there is more variation
in the selling prices of the oceanfront homes?

19. In a particular market there are three commercial television stations, each with its own
evening news program from 6:00 to 6:30 P.M. According to a report in this morning's local
newspaper, a random sample of 150 viewers last night revealed 53 watched the news
on WNAE (channel 5), 64 watched on WRRN (channel 11), and 33 on WSPD (channel 13).
At the .05 significance level, is there a difference in the proportion of viewers watching
the three channels?