Based on an analysis of sample data, an article proposed the pdf fx) -0.556-05-) when x 21 as a model for the distribution of X-time (sic) spent at the median line. (Round your answers to three decimal places) (a) What is the probability that waiting time is at most o sac? More than 5 sec? at most 6 sec P(X 6) - more than 6 sec P(X>6) (b) What is the probability that waiting time is between 3 and 8 sec?