4. Not happy with the previous results, the analyst in Exercise 2 takes a much larger random sample of customers from each website and records their page views.

Here are the data:

a) Find the estimated mean difference in page visits between the two websites.

b) Find the standard error of the estimated mean difference.

c) Calculate the t-statistic for the observed difference in mean page visits assuming that the true mean difference is 0.
Website A Website B 9 10 4 13 14 2 7 3 2 7 Neighborhood 1 Neighborhood 2 n1 = 30 n2 = 35 y1 = 57.2 yrs y2 = 47.6 yrs s1 = 7.51 yrs s2 = 7.85 yrs SECTION 14.2

Website 1 Website 2 n = 80 2 = 95 1 J = 7.7 pages 7.7 pages 72 = 7.3 pages S = 4.6 pages S = 4.3 pages