Question

Construct a 99% confidence interval of the population proportion using the given information.

x=75, n=150

The lower bound is?

The upper bound is?

99% confidence has an area of each tail, alpha/2 is .005, and critical value is 2.575 (z alpha/2)

Answer 1

sample success x =		75
sample size          n=		150
sample proportion p̂ =x/n=		0.5000
std error se= √(p*(1-p)/n) =		0.0408
for 99 % CI value of z=		2.575
margin of error E=z*std error   =		0.1051
lower bound=p̂ -E                       =		0.395
Upper bound=p̂ +E                     =		0.605