The National Sleep Foundation used a survey to determine whether hours of sleep
ID: 3134488 • Letter: T
Question
The National Sleep Foundation used a survey to determine whether hours of sleep 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.
Conduct a test of independence to determine whether the hours of sleep on weeknights are independent of age. Use = .05.
Compute the value of the 2 test statistic (to 2 decimals).
The p value is
A-less than .005
B-between .005 and .01
C-between .01 and .025
D-between .025 and .05
E-between .05 and .10
F-greater than .10
What is your conclusion?
A-Conclude age and hours of sleep are not independent
B-Cannot reject the assumption that age and hours of sleep are independent
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).
Hours of Sleep Age Fewer than 6 6 to 6.9 7 to 7.9 8 or more Total 49 or younger 31 64 72 73 240 50 or older 37 56 77 90 260Explanation / Answer
Using excel we get the following
p value is greater than 0.10.
The conclusion is cannot reject the assumption that age and hours of sleep are independent.
Chi-square Contingency Table Test for Independence Fewer than 6 6 to 6.9 7 to 7.9 8 or more Total Total 49 or younger Observed 31 64 72 73 240 480 (O - E)² / E 0.08 0.71 0.00 0.35 0.00 1.15 % of chisq 3.7% 32.2% 0.1% 15.9% 0.0% 52.0% 50 or older Observed 37 56 77 90 260 520 (O - E)² / E 0.08 0.66 0.00 0.32 0.00 1.06 % of chisq 3.4% 29.7% 0.1% 14.7% 0.0% 48.0% Total Observed 68 120 149 163 500 1000 (O - E)² / E 0.16 1.37 0.01 0.67 0.00 2.21 % of chisq 7.2% 62.0% 0.3% 30.6% 0.0% 100.0% 2.21 chi-square 4 df .6977 p-valueRelated Questions
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