Tutorial solutions week 13

3 4 a public health researcher is interested in

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Unformatted text preview: researcher is interested in testing whether the level of beer consumption of individuals is independent of their level of cigarette consumption. A random sample of 1,000 individuals are interviewed about their weekly consumption of beer and cigarettes, yielding the following bivariate frequency distribution: nil nil Cigarette 1-20 cons. 21-60 >60 256 105 71 22 Beer consumption 1-3 4-10 glasses glasses 68 54 110 87 56 25 26 17 Over 10 glasses 25 42 26 10 Given the data, perform a test of independence of beer and cigarette consumption using a 5% significance level. The expected cell frequencies are given in brackets in the following table. nil nil Cig. cons. 256 (182.962) 1-20 105 (156.176) 21-60 71 (80.812) >60 22 (34.05) Col. 454 Total Beer consumption 1-3 4-10 Over 10 Row glasses glasses glasses total 68 54 25 403 (104.78) (73.749) (41.509) 110 87 42 344 (89.44) (62.952) (35.432) 56 25 26 178 (46.28) (32.574) (18.334) 26 17 10 75 (19.5) (13.725) (7.725) 260 183 103 1000 4 e.g. ( )( ) Now the test statistic is given by ∑∑ ( ) ( And since we reject consumption are not independent. ) ( ) and conclude that beer and cigarette 5...
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