The average prime member spends $5,010 a year on the website shopping a wide assortment of goods. In order to increase sales, Amazon starts offering Two Hour Prime Delivery (you can order stuff on Amazon.com and it gets delivered to you in 2 hours or less) to a random sample of 99 prime customers. You are hired by Amazon to analyze if the introduction of Two Hour Prime delivery increases sales for Amazon. You find that the 99 random prime customers that were offered Prime Delivery spent $5,125 on Amazon with a standard deviation of $490 in sales. (Without using MINITAB)
(A) Test whether the introduction of Two Hour Prime Delivery increased sales for Amazon.com. Set up your null and alternative hypotheses. Test at the 95% level of significance. Show your test and critical statistics. Did Two Hour Delivery significantly increase sales?
(B) Construct a 99% confidence interval.