According to a survey by TD Ameritrade, one out of fourinvestors has exchange-traded funds in their portfolios (USAToday, January 11, 2007). Consider a sample of 40investors.
Compute the probability of exactly 7 investors havingexchange-traded funds in their portfolio.
Compute the probability that at least 5 of the investors haveexchange-traded funds in their portfolio.
Compute the probability that at most 4 of the investors haveexchange-traded funds in their portfolio.
Find the mean and standard deviation.
If you found that exactly 10 of the investors haveexchange-traded funds in the
portfolio would you doubt the accuracy of the survey andwhy?
