In the Health ABC Study, 537 subjects owned a pet and 1999 subjects did not. Amo
ID: 3059761 • Letter: I
Question
In the Health ABC Study, 537 subjects owned a pet and 1999 subjects did not. Among the pet owners, there were 294 women; 965 of the non-pet owners were women. Find the proportion of pet owners who were women. Do the same for the non-pet owners. (Be sure to let Population 1 correspond to the group with the higher proportion so that the difference will be positive. Round your answers to three decimal places.) P2= Give a 95% confidence interval for the difference in the two proportions. (Do not use rounded values. Round your final answers to three decimal places.) eBookExplanation / Answer
P1 = Proportions of Pet Owners who were women = 294/537 = 0.547
P2 = Proportion of Non-Pet Owners who were women = 965/1462 = 0.660
95% CI for diff of proportions:
P1- P2 +- Z*SE
SE1 = Sqrt(P1(1-P1)/n1) = sqrt(0.547*0.453/537)=0.0214
SE2 = Sqrt(P2(1-P2)/n2) = sqrt(0.66*0.34/1462)= 0.0123
SE = sqrt(SE1^2+SE2^2) = 0.024
CI = (0.66-0.547)+-1.96*0.024
At 95% CI, Z=1.96
CI = 0.113+-0.047 = (0.066 , 0.16)
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