Environment: Pollution Index Based on information from The Denver Post, a random sample of n1 512 winter days in Denver gave a sample mean pollution index of x1 5 43. Previous studies show that s1 5 21.

For Englewood (a suburb of Denver), a random sample of n2 514 winter days gave a sample mean pollution index of x2 5 36. Previous studies show that s2 515.

Assume the pollution index is normally distributed in both Englewood and Denver. Do these data indicate that the mean population pollution index of Englewood is different (either way) from that of Denver in the winter? Use a 1% level of significance.

AppendixLO1