The Centers for Disease Control and Prevention (CDC) published on 2/19/2016 the
ID: 3240611 • Letter: T
Question
The Centers for Disease Control and Prevention (CDC) published on 2/19/2016 the results of an analysis of the 2014 Behavioral Risk Factor Surveillance System (BRFSS) concerning healthy sleep among American adults. (Healthy sleep is defined as greaterthanorequalto 7 hours of sleep on a typical 24-hour period). See 1.htm for more details. Table 1 (http: /www.cdc.gov/mmwrivolumes/65Mwrmm6506a1.htm#T1 down) reports among others, the proportion of adults getting healthy sleep by race/ethnicity. The slightly simplified results are summarized in the Table below. Fill in the missing cells in the Table Use Pearson's Chi-square test (in SPSS or by hand) to test the overall hypothesis that all three race/ethnicity groups have the same proportion of reported healthy sleep. If you found a significant difference b), do the three pairwise comparisons of the ethnicity/race groups, with a Bonferroni correction: White vs. Black, White vs. Hispanic, Black vs. Hispanic, and discuss your findings.Explanation / Answer
a.
b. Null Hypothesis : H0 : All Proportions are same.
ALternative Hypothesis : Ha : At least one proportions are not same.
chi - square table
so value of chi- square X2 = 748.89
(c) dF = 2 and alpha = 0.05 critical chi- square = 5.991
so significant difference exists.
Number of subjects >= 7 sleep <7th sleep Total Proportions getting >=7 sleep White 230460 114540 345000 0.668 Black 18428 15572 34000 0.542 Hispanic 18995 10005 29000 0.655 Total 267883 140117 408000 0.6566