Exam 11: Probability Basics

Use the following A statistician used a computer to generate 4 random values between 0 and 9. Let X represent the number of these values that are 5 or larger. Round all probability calculations to three decimal places. -If a "success" is being 5 or larger, what is the probability of success in this situation?

Use the following When a certain pitcher throws his fastball, 75% of the time it is a strike. Suppose he throws 20 fastballs and that the pitches are independent of one another. Let X represent the number of strikes in 20 pitches. Round all answers to three decimal places. -Find the mean of the random variable X.

Use the following There are three roofing companies that service a small community. Al's Roof Repair gets 45% of the roofing jobs in the community while Bob's Better Building and Carl's Roof Service get 25% and 30% of the business, respectively. Of Al's customers, 70% are satisfied. Of Bob's customers, 95% are satisfied. Among Carl's customers, 90% are satisfied. Round all answers to four decimal places. -If a randomly selected customer is satisfied, what is the probability that they used Carl's Roof Service?

Use the following The New York Lottery has a daily game called "Take Five" where you win prizes based on how many of the 5 selected numbers match your ticket. The probability function for the typical payout on a ticket (X) is displayed in the provided table. Round all answers to two decimal places. -Compute the variance of the typical payout of a "Take Five" ticket.

Use the following Suppose A and B are independent events with P(A) = 0.21 and P(B) = 0.81. -Find P(A or B). Round your answer to four decimal places.