It has become more common for shoppers to comparison shop using the Internet. Respondents to a Pew survey in 2013 who owned cell phones were

It has become more common for shoppers to €œcomparison shop€ using the Internet. Respondents to a Pew survey in 2013 who owned cell phones were asked whether they had, in the past 30 days, looked up the price of a product while they were in a store to see if they could get a better price somewhere else. Here is a table of their responses by income level.

a) Is the frequency of comparison shopping on the Internet independent of the income level of the respondent? Perform an appropriate chi-square test and state your conclusion.
b) Calculate and examine the standardized residuals. What pattern (if any, do they show that would be of interest to retailers concerned about cybershopping comparisons?

< $30K 207 625 $30K $49.9K 115 406 $50K $74.9K > $75K Yes No 134 260 204 417