Cumulative Exam — Cumulative exam Answers

Car insurance companies want to keep track of the average cost per claim. The current data in use for Auto Insurance R Us is an average of $2,200 for each claim with a standard deviation of $500. With this average, the company can stay competitive with rates but not lose money. However, the statistician for the company believes that the cost of the average claim has increased. He pulled 40 recent claims and found the average to be $2,350. Which most restrictive level of significance would suggest that the company should raise rates? Upper-Tail Valuesa5%2.5%1%Critical z-values1.651.962.58

Matrices X and Y both measure and are inverses of each other. Which matrix represents their product?

A normal distribution of data has a mean of 90 and a standard deviation of 18. What is the approximate z-score for the value 64?

Johnni guessed on all 8 questions of a multiple-choice quiz. Each question has 4 answer choices. What is the probability that she got exactly 3 questions correct? Round the answer to the nearest thousandth.

What is the product?

Which equation is y = –6x2 + 3x + 2 rewritten in vertex form?

Vladimir rolls a six-sided number cube 36 times. If getting a 3 is a success, what is the probability of a success?

If (x – 5) is a factor of f(x), which of the following must be true?

What is the value of i 20+1?

Laila guesses on all 20 questions of a multiple-choice test. Each question has 4 answer choices. What is the probability of a success and a failure for this experiment?