DHOGHN BLUEB TRUONG DAI HOC KINH TE - DAI HOC QUOC GIA HA NOI Subject: Principles of Economics Statistics Date: 20 /04/2022 Location: E 511 Duration of test: 90 minutes Question 1 (2 points) Suppose P(A) = 5 , P(B) = 3 , and P(A U B) = 2. a. Find P(An B), P(BIA), and P(A|B). b. Are A and B independent events? Justify your answer. Question 2 (2 points) The following table provides a probability distribution for the random variable x. X f (x) 3 0.25 6 0.50 9 0.25 a. Compute E(x), the expected value of x. b. Compute s2, the variance of x. c. Compute s, the standard deviation of x Question 3 (2 points) When entering a new market, an enterprise can only expect to achieve an average of 30 thousand of USD/month in sales and a standard deviation of 5 thousand of USD. Find the probability that when entering that market, the business will have sales of at least 32 thousand of USD/month. Note: + Document and mobile phone are not allowed to use. + Supervisor's name: ....... . . . ... ......Mobile phone number