The National Sleep Foundation used a survey to determine whether hours of sleepi

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 36 56 72 76 240 50 or older 37 55 78 90 260 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 %

Explanation / Answer

applying chi square test of independence on above:

from above test statistic =0.64

p value =0.886 ( please try 0.887 if this does not work due to rounding.

Observed Oi <=49 >=50 Total <6 36 37 73 6.6-6.9 56 55 111 7-7.9 72 78 150 >=8 76 90 166 Total 240 260 500 Expected Ei=row*column/total <=49 >=50 Total <6 35.040 37.960 73 6.6-6.9 53.280 57.720 111 7-7.9 72.000 78.000 150 >=8 79.680 86.320 166 Total 240 260 500 chi square =(Oi-Ei)2/Ei <=49 >=50 Total <6 0.0263 0.0243 0.051 6.6-6.9 0.1389 0.1282 0.267 7-7.9 0.0000 0.0000 0.000 >=8 0.1700 0.1569 0.327 Total 0.335 0.309 0.6445

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.