Guessing on a Test The designers of a true-false test would like to find out how a student would perform if the student just guessed all the answers at random. (Designers of multiple-choice tests like the SAT have to consider this issue as well.) There are 100 questions on the test. One point is awarded for each correct answer and 1 point is taken away for any other kind of answer (wrong, missing, ambiguous, or anything other than correct). The test designers have figured out that the number of questions the student gets right by guessing at random has expectation 50 and SD 5 a) Let W be the number of questions the student does not get right. Find E(W) and SD(W). b) Let S be the student's score on the test. Find E(S) and SD(S).

Jamie went to home depot.she bought 25 bags of soil that cost $9 per bag.she bought 15 pots at $8 each,and she bought 23 bags of pebbles at $15 each.she used a coupon that gave her $5 off for every 100 dollars she spent.how much did jame pay at the end?

Astore has apples on sale for three dollars or 2 pounds how many pounds of apples can you buy for nine dollars if an apple is approximately 5 ounces how many apples can you buy for nine dollars

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?