One hundred draws are made at random with replacement from box a, and 250 are madeat random from box b.(a) 50 of the draws from box a are positive, compared to 131 from box b: 50.0% versus52.4%. is this difference real, or due to chance? (b) the draws from box a average 1.4 and their sd is 15.3; the draws from box b average6.3 and their sd is 16.1. is this difference between the averages statistically different?