# Question: Describe how to compute the mean or expected value of

Describe how to compute the mean (or expected value) of a discrete random variable, and interpret what this quantity tells us about the observed values of the random variable.

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Describe how to compute the standard deviation of a discrete random variable, and interpret what this quantity tells us about the observed values of the random variable. Refer to Exercise 6.11. a. Calculate the mean flight time and the standard deviation of the flight time. b. Find the probability that the flight time will be within one standard deviation of the mean. If the random variable z has a standard normal distribution, sketch and find each of the following probabilities: a. P(0 ≤ z ≤ 1.5) b. P(z ≥ 2) c. P(z ≤ 1.5) d. P(z ≥ – 1) e. P(z ≤ – 3) f. P(– 1 ≤ z ...An investment broker reports that the yearly returns on common stocks are approximately normally distributed with a mean return of 12.4 percent and a standard deviation of 20.6 percent. On the other hand, the firm reports ...Suppose that x has a binomial distribution with n = 200 and p = .4. a. Show that the normal approximation to the binomial can appropriately be used to calculate probabilities about x. b. Make continuity corrections for ...Post your question