b. (4 pts) between 4.4 and 4.6 minutes? Solution: The problem asks for Pr(4.4 g X g 4.6) . This is equivalent to Pr( X s 4.6) _ Pr(X s 4.4). Let Z be a stande normal random variable, 2 = X _ \"X 0X Then when x = 4.6 , 4.6 A 3.54 z = 4.24 , 0.25 and Pr( X g 4.6) = Pr( 2 $4.24). From the normal table, Pr(Z g 4.24) g1, When x = 4.4 , 4.4 3.54 z = 3.44 , 0.25 and Pr( X g 4.4) = Pr( 2 $3.44). From the normal table, Pr(Z g 3.44) = .9997 . Therefore