Question 1174838
p1=35/250=0.14
p2=27/300=0.09
p1-p2 point estimate is 0.05
std error is sqrt { (p hat*(1- phat)* (1/n1)+(1/n2)} p hat is pooled proportion or 62/550=0.1127
=sqrt ((p1*(1-p1)/n1+p2(1-p2)/n2))=sqrt(0.14*0.86/250+0.09*0.91/300)=0.0275
multiply that by 1.96 to get the half-interval of the difference at the 95% level=0.0538

CI=(-0.0038, 0.1038)

for 90%, use 1.645 and get a half-interval of 0.0452
CI=(0.0048, 0.0952)

Notice the first contains 0, so the p-value is between 0.05 and 0.10