6. How many different ways can a singing group consisting of 5 sopranos and 4 altos be selected out of a larger group of 7 sopranos and 9 altos? 7. Does the following represent a probability distribution? If so, calculate the expected value, if not, state why. X 8 12 16 20 venis toation [ desol in anieeaud P(X) 5/6 1/12 1/12 1/12 etowene was noomi on arilezevo .b 8. A bank has a drive-through service. The number of customers arriving during a 15 minute period is distributed as shown. Find the mean and standard deviation for the distribution. X 0 1 2 3 4 P(X) |0.12 0.20 0.31 0.25 0.12 9. Let x be a binomial random variable with n = 12 and p = 0.3. Find the following. a. P(X = 8) b. P(X