A race director is preparing for an upcoming marathon and estimates that the mean time to finish is 310 minutes. Assume
that the times are normally distributed, with a standard deviation of 50 minutes.
Use a standard normal table or a calculator to find the percentage of times that are longer than 236 minutes. For your
intermediate computations, use four or more decimal places. Give your final answer to two decimal places (for example
98.23%).

Amachine that produces a special type of transistor (a component of computers) has a 2% defective rate. the production is considered a random process where each transistor is independent of the others. (a) what is the probability that the 10th transistor produced is the first with a defect? (b) what is the probability that the machine produces no defective transistors in a batch of 100? (c) on average, how many transistors would you expect to be produced before the first with a defect? what is the standard deviation? (d) another machine that also produces transistors has a 5% defective rate where each transistor is produced independent of the others. on average how many transistors would you expect to be produced with this machine before the first with a defect? what is the standard deviation? (e) based on your answers to parts (c) and (d), how does increasing the probability of an event a↵ect the mean and standard deviation of the wait time until success?