Do people tend to spend more money on fast-food when they use a credit card? The following data represent a random sample of credit-card and cash purchases.
(a) Draw boxplots of each data set using the same scale. What do the boxplots imply for cash versus credit?
(b) Test whether the sample evidence suggests that people spend more when using a credit card. Use the α = 0.01 level of significance.
(c) Suppose that you were looking to gather evidence to convince your manager that an effort needs to be made to boost credit-card sales. Would it be legitimate to change the level to α = 0.05 after seeing the results from part (b)? Why?

  • CreatedApril 28, 2015
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