Once an individual has been infected with a certain disease, let X represent the time (days) that elapses before the individual becomes infectious. An article proposes a Weibull distribution with a = 2.4, = 1.2, and y = 0.5. [Hint: The two-parameter Weibull distribution can be generalized by introducing a third parameter y, called a threshold or location parameter: replace x in the equation below, -le-(x/B) f(x; , B)= Ba by x - y and x 0 by x y.] (a) Calculate P(1 < X < 2). (Round your answer to four decimal places.) 0.7037 mean 0 (b) Calculate P(X> 1.5). (Round your answer to four decimal places.) 0.5243 x 0 (c) What is the 90th percentile of the distribution? (Round your answer to three decimal places.) 2.1987 days. standard deviation x < 0 (d) What are the mean and standard deviation of X? (Round your answers to three decimal places.) days days Need Help? Read It