SOLUTION: Two samples are taken with the following numbers of successes and sample sizes r1 = 29 r2 = 31 n1 = 63 n2 = 77 Find a 98% confidence interval, round answers to the nearest

Algebra ->  Probability-and-statistics -> SOLUTION: Two samples are taken with the following numbers of successes and sample sizes r1 = 29 r2 = 31 n1 = 63 n2 = 77 Find a 98% confidence interval, round answers to the nearest      Log On


   

Question 1157147: Two samples are taken with the following numbers of successes and sample sizes
r1 = 29
r2 = 31
n1 = 63
n2 = 77
Find a 98% confidence interval, round answers to the nearest thousandth.
_______ < p1−p2 < _______

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
This is ready made to be put into a calculator.
(-.14, +.25) is the 98% CI.
By hand, the half-interval or z*SE is z(0.99)*sqrt (p1(1-p1)/n1)+(p2(1-p2)/n2))
=2.33*sqrt(0.00706)
and to rounding error, you get a half-interval of 0.195, which is half the difference between -.14 and +.25 above.