Question

The National Sleep Foundation used a survey to determine whether hours of sleeping per night are independent of age (Newsweek, January 19, 2004). The following show the hours of sleep on weeknights for a sample of individuals age 49 and younger and for a sample of individuals age 50 and older.

Hours of Sleep

Age

Fewer than 6

6 to 6.9

7 to 7.9

8 or more

Total

49 or younger

40

65

70

65

240

50 or older

31

59

71

99

260

Conduct a test of independence to determine whether the hours of sleep on weeknights are independent of age. Use

= .05. Use Table 12.4.

Compute the value of the

2 test statistic (to 2 decimals).

The p value is

What is your conclusion?

Using the total sample of 500, estimate the percentage of people who sleep less than 6, 6 to 6.9, 7 to 7.9, and 8 or more hours on weeknights (to 1 decimal).

Less than 6 hours

%

6 to 6.9 hours

%

7 to 7.9 hours

%

8 or more hours

%

Answer 1