For a standard normal distribution whats the probability of getting a positive number

Alength on a map is 7.5 inches. thescale is 1 inch: 5 miles. what is theactual distance? a 1.5 miles c 12.5 milesb 2.5 miles d 37.5 miles

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?

Interpret the following expression (5y^2-7)^3/(2y)^2