The National Center for Health Statistics reported the following data on the number of children born in individual pregnancies in 1996 and 2006 (The World Almanac, 2010):
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a. Define a random variable x = number of children born in a single pregnancy in 1996 and develop a probability distribution for the random variable. Let x = 5 represent quintuplets or more.
b. Compute the expected value and variance for the number of children born in a single pregnancy in 1996.
c. Define a random variable y = number of children born in a single pregnancy in 2006 and develop a probability distribution for the random variable. Let y = 5 represent quintuplets or more.
d. Compute the expected value and variance for the number of children born in a single pregnancy in 2006.
e. Do these data support the conclusion that the increased use of fertility drugs by older women has generated an upward trend in multiplebirths?