Question 463145
0 kids: n=122, mu[0]=7.42, s=3.92
1 kid: n=120, mu[1]=6.72, s=4.04
.
H[o]:mu[0]=mu[1]
H[a]:mu[0]<>mu[1]
.
{{{sigma(x[0]-x[1])=sqrt((3.92/122)+(4.04/120))=sqrt(.0321+.0337)=0.257}}}
z=(7.42-6.72)/0.257=2.72
.
Since z=2.72 is in the rejection zone beyond 1.96 then the null hypothesis is rejected.
.
Ed