Online shopping statistics are routinely reported by www.shop.org. Of interest to many online retailers are gender-based differences in shopping preferences and behaviours. The average monthly online expenditures are reported for males and females:

a) Find 95% confidence intervals for the average monthly online expenditures for males and females.

b) These intervals overlap. What does this suggest about any gender-based difference in monthly online expenditures?

c) Find a 95% confidence interval for the difference in average monthly online expenditures between males and females.

d) The two results seem contradictory. Which method is correct: doing two-sample inference, or doing one-sample inference twice?

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Male Female 45 45 $352 $310 Mean $95 $80 StDev dnojg