Question 460948
H[o]:p<.2 NOT what you have above. He claims that LESS than 20% of his life insurance policies ever have to "pay out." The null hypothesis should be what HE claims.
p[o]=.20, q[o]=.80, 
n=75, P=30/75 = .4
s=sqrt(.2*.8*75)=sqrt(12)=3.46
m=.2*75=15
.
{{{z=(p-p[o])/sqrt((p[o]*q[o])/n)=(.4-.2)/sqrt((.2*.8)/75)}}}
=.2/.0462
=4.33
The critical value should be 2.05 NOT -2.05
4.33 is way above 2.05 and the null hypothesis is rejected.
.
Ed