Construct a 90% confidence interval for (p1-p2) in each of the following situations:

Construct a 90% confidence interval for (p1-p2) in each of the following situations:

a) n1=400; p1 =0 .67; n2 = 400; p2 =0.58

b) n1 =180; p1 =0.29; n2 = 250; p2 =0.27

c)n1 = 100; p1 = 0.44; n2 = 120; p2 =0.59

90% confidence interval for each