A survey asked American adults cell phone owners if they browse the internet almost exclusively on their phone rather than a computer or other device. Of 1150 respondents ages 35 and above, 12% answered yes. Of 1025 respondents ages
22 to 34, 18% answered yes.
(a) Calculate a 98% confidence interval for the difference in proportion who access the internet almost exclusively on their
cell phones for the two groups of Amerian adults. State all necessary conditions.
(b) Provide an interpretation of the interval in context. Is there evidence in support of a difference? Explain.

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?