Heather is saving for retirement and has been doing a lot of research on how much she should put aside each month. the newest article says that 1/36 of her salary should be put into a retirement account. if she makes $63,000 a year, how much will she put into her retirement account each month (rounded to the nearest dollar)?
a) $1,750
b) $210
c) $145
d) $5,250

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?