Website visitors are often loath to disclose personal information when making a purchase on the Internet. Despite safeguards in place, nearly 60% of all consumers who make purchases on the Internet do not feel comfortable giving their credit card number. Suppose that X is a random variable that represents the number of website purchasers who do not feel comfortable typing their credit card numbers online from a sample of 20 purchasers.
a) Why is X a binomial random variable?
b) What is the probability that X is less than six?
c) Would you consider the event of X less than six to be unusual?
d) What value would you expect X to be on average? What is the standard deviation of X?