Based on an analysis of sample data, an article proposed the pdf f(x) = 0.35e-0.35(x - 1) when x 2 1 as a model for the distribution of x = time (sec) spent at the median line. (Round your answers to three decimal places.) (a) What is the probability that waiting time is at most 6 sec? More than 6 sec? at most 6 sec P(XS 6) = more than 6 sec P(X> 6) = (b) What is the probability that waiting time is between 4 and 6 sec?