A marketing research firm is interested in determining whether there is difference between households in Chicago and Milwaukee in the degree that they purchase groceries online. The research firm decided to randomly sample household earners with income of $50,000 per year in the two cities and ask them had they purchased groceries online during the last year. The results of the survey showed that of the 150 sampled in CHicago 19 and yes which in Milwaukee of 135 sampled 10 said yes.
Construct a 95% Confidence interval for diffrence between the two populations. At the alpha equals .10 level of significance, can the firm conclude that Chicago households buy more online than Milwaukee.
Do a formal Hypothesis test.