Question 1192785
z=(x-mean)/sigma/sqrt(n)
z=(14.75-15.85)/9.5/sqrt(12)=-1.10*sqrt(12)/9.5=-0.40
z=(22.5-15.85)/9.5/sqrt(12)=2.42
that probability is 0.6477.
The sd of the sample mean is 9.5/sqrt(12)=2.74
There is rounding of the z value above. If done on the calculator without rounding, the probability is 0.6481.