According to the South Dakota Department of Health the mean

According to the South Dakota Department of Health, the mean number of hours of TV
viewing per week is higher among adult women than men. A recent study showed
women spent an average of 34 hours per week watching TV and men 29 hours per
week. Assume that the distribution of hours watched follows the normal distribution for both
groups, and that the standard deviation among the women is 4.5 hours and is 5.1 hours
for the men.
a. What percent of the women watch TV less than 40 hours per week?
b. What percent of the men watch TV more than 25 hours per week?
c. How many hours of TV do the 1% of women who watch the most TV per week watch?
Find the comparable value for the men.

Solution

a.)P(W<38)=P(Z<38-36/4.8)=P(z<0.42)=0.6628 b.)P(M>25)=P(Z>25-30/5.2)=P(Z>-0.96)=0.8315 c.)1.89=x-36/4.8 So x=45.072