Let f(x) = cxe−x2 if x ≥ 0 and f(x) = 0 if x < 0. (a) For what value of c is f a probability density function?

(b) For that value of c, find P(1 < X < 3).

Assume that adults have iq scores that are normally distributed with a mean of mu equals 100 and a standard deviation sigma equals 20. find the probability that a randomly selected adult has an iq between 80 and 120.assume that adults have iq scores that are normally distributed with a mean of mu equals 100 and a standard deviation sigma equals 20. find the probability that a randomly selected adult has an iq between 80 and 120.