The Centers for Disease Control and Prevention reports that 25% of baby boys 6–8 months old in the United States weigh more than 20 pounds. A sample of 16 babies is studied.

a. What is the probability that exactly 5 of them weigh more than 20 pounds?

b. What is the probability that more than 6 weigh more than 20 pounds?

c. What is the probability that fewer than 3 weigh more than 20 pounds?

d. Would it be unusual if more than 8 of them weigh more than 20 pounds?

e. What is the mean number who weigh more than 20 pounds in a sample of 16 babies aged 6–8 months?

f. What is the standard deviation of the number who weigh more than 20 pounds in a sample of 16 babies aged 6–8 months?