A sample of 1 1 1 observations indicated that X 1 is 7 6 . A second sample of 1 5 8 observations indicated that X 2 is 8 7 . Conduct a z - test of hypothesis about a difference in population proportions using a 0 . 0 2 significance level. H0 : p1 - p2 = 0 H1 : p1 - p2! = 0