In: Statistics and Probability
            The National Sleep Foundation used a survey to determine whether
hours of sleeping per night are...
                
            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 | 
39 | 
58 | 
71 | 
72 | 
240 | 
 | 
 | 
50 or older | 
32 | 
56 | 
77 | 
95 | 
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 Selectless than .005between .005 and
.01between .01 and .025between .025 and .05between .05 and
.10greater than .10Item 2
What is your conclusion?
SelectConclude age and hours of sleep are not independentCannot
reject the assumption that age and hours of sleep are
independentItem 3
 
- 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 | 
% |