A random sample of n, = 18 winter days in Denver gave a sample mean pollution Index x, = 43. Previous studies show that o = 13. For Englewood (a suburb of Denver), a random sample of n, = 14 winter days gave a sample mean pollution index of x, = 38. Previous studies show that o, = 17. 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.. (a) What is the level of significance? State the null and alternate hypotheses. O HO: H1 = H2iH1: H1 H2 O Ho: H,