27 A sleeplab study found that a group of subjects with a m

____ 27. A sleep-lab study found that a group of subjects with a mean age of about 68 years slept significantly less than the group of subjects with a mean age of 22 years, with the former averaging only 7.4 hours and the latter 8.9 hours. In contrast, an ANOVA procedure on student survey data found no significant difference in hours slept among 1st, 2nd, 3rd, and 4th year students. In general, to produce evidence of a relationship between sleep and age, which is more helpful?

a) include individuals who are all roughly the same age

b) include individuals spanning a wide range of ages

c) it doesn\'t matter how similar or different the ages are

Is there a difference in mean price of homes in areas north, south, east, and west of a certain city? Analysis of variance was carried out on samples of homes in a local open house directory:

____ 28. For an F distribution with 3 degrees of freedom in the numerator and 36 in the denominator, the F statistic 4.35 is

a). large

b). not large

c). we have no way of knowing

Is there a difference in mean hotel rates (five-night stay) for all hotels in Jamaica Curacao, and St. Lucia? Analysis of variance was carried out on samples of hotels a each of the three resorts:

____ 29. The sample sizes are relatively

a. small

b. large

____ 30. Which two resorts differed the most?

a. Jamaica and Curacao

b. Jamaica and St. Lucia

c. Curacao and St. Lucia

____ 31. Is there a significant difference among rates for hotels in the three resorts?

a. yes

b. no

____ 32. Which one of these would have given us less evidence of a difference among hotel rates?

if the sample means had been closer together

if sampled rates had been spread out less around the three group means

if similar means and standard deviations had arisen from larger samples of hotels

ANOVA was used to compare samples of weekly hotel rates at three Mexican resorts: Cancun, Puerto Vallarta, and Los Cabos.

____ 33. What does the null hypothesis state?

The New York Times reported on the economic impact of 10 evacuations at American airports in 2003, with information on the duration of the evacuation (in minutes) and the cost (in millions of dollars). The regression of cost on duration resulted in the following output.

The regression equation is
Cost = -1.11 + 0.0556 Duration

Coef

SE Coef

T

P

-1.1113

0.5181

-2.14

0.064

0.055620

0.008119

6.85

0.000

____ 34. Altogether there were 120 evacuations at American airports that year. The slope of the regression line for the relationship between duration and cost for all 120 evacuations is

0.0556

a. unknown, but it must be positive

b. unknown, but almost surely positive

c. unknown, and it could easily be negative

A newspaper published base pay and cash bonus for C.E.O.s of a sample of large companies in 2006. A regression was performed to explore the relationship between the two variables.

The regression equation is
Bonus = 418 + 2.85 Pay

Coef

SE Coef

T

P

418

4197

-2.14

0.064

2.854

3.254

0.88

0.406

____ 35. The slope of the regression line for the relationship between all executives\' pay and bonus is

a). 2.85

b). unknown, but almost surely positive

c). unknown, and it could easily be zero or negative

Predictor	Coef	SE Coef	T	P
Constant	-1.1113	0.5181	-2.14	0.064
Duration	0.055620	0.008119	6.85	0.000

Solution