Two students are comparing scientific experiments to investigations. They came up with the following ideas. Student A: Testing plant growth in different types of soils

Student B: Comparing the water level in a lake during different times of the year Which student gave an example of a scientific experiment? (5 points)

A: Student A because it requires experimental and control groups
B; Student B because it requires a hypothesis
C: Student A because it is preferably done in natural settings
D: Student B because it is preferably done across a long period of time

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?