Two Sample Hypothesis Tests
A survey of 100 mayonnaise purchasers showed that 65 were loyal to one brand. For 100 bath soap purchasers, only 53 were loyal to one brand. (a) Perform a two-tailed test comparing the proportion of brand-loyal customers at alpha = .05. (b) Form a confidence interval for the difference of proportions, without pooling the samples. Does it include zero?