19:27 115128351 ... a 49%[:] unsw.mobius.cloud ti 2020 T3 EXAM Let X1, X2, X3 be independent normal random variables which all have mean 13.8 and standard deviation 0.9. 1) a) Find the mean of X1 + 2X2 4X3. a: (exact value) b) Compute the standard deviation of X1 + 2X2 4X3. , .-a Elias (enter your answer correct to at least 3 decimal places) c) Calculate P(X1 + 2X2 4X3 g 16.69) [1 (enter your answer correct to at least 2 significant figures) 2) a) State P(X1 > 14.43) 1 3] (enter your answer correct to at least 3 significant figures) b) Calculate P(X1 > 14.43 | X1 > 13.35) 1 3! (enter your answer correct to at least 3 significant figures) c) Find P(X1 > 14.43 X2 > 13.35) I ' (enter your answer correct to at least 3 significant figures) teams H Lamar; l l to H 1%an i see