Answer to Question #300490 in Statistics and Probability for Tzuyu

Question

In 2012 the Centers for Disease Control and Prevention reported that the rate of autism in children has risen to in 50. A study conducted in Norway suggests that the risk of autism may be significantly lower if women take folic acid supplements during pregnancy. Suppose a large medical center enlists 900 expectant mothers in a trial; the women agree to take the folic acid for the duration of their pregnancies. The researchers will track the children after birth to see how many develop autism.

a) Explain why the number of autism cases is a binomial random variable.

b) If folic acid supplements actually have no effect, what is the mean and standard deviation of the number of autism cases that these researchers might find ?