Probability Distribution Functions Review

State whether the variable is discrete or continuous. The number of cups of coffee sold in a cafeteria during lunch

• continuous

• discrete

State whether the variable is discrete or continuous. The speed of a car on a Los Angeles freeway during rush hour traffic

• continuous

• discrete

The random variable x represents the number of cars per household in a town of 1000 households. Find the probability of randomly selecting a household that has less than two cars.

• 0.125

• 0.809

• 0.553

• 0.428

Determine the probability distribution's missing value. The probability that a tutor will see 0, 1, 2, 3, or 4 students

• -10/21

• 2/21

• 20/21

• 1/21

The random variable x represents the number of boys in a family of three children. Assuming that boys and girls are equally likely, find the mean and standard deviation for the random variable x.

• mean: 1.50; standard deviation: 0.76

• mean: 1.50; standard deviation: 0.87

• mean: 2.25; standard deviation: 0.87

• mean: 2.25; standard deviation: 0.76

In a pizza takeout restaurant, the following probability distribution was obtained. The random variable x represents the number of toppings for a large pizza. Find the mean and standard deviation.

• mean: 1.30; standard deviation: 2.38

• mean: 1.14; standard deviation: 1.04

• mean: 1.30; standard deviation: 1.54

• mean: 1.54; standard deviation: 1.30

At a raffle, 10,000 tickets are sold at $10 each for three prizes valued at $4,800, $1,200, and $400. What is the expected value of one ticket?

• $0.64

• -$0.64

• $9.36

• -$9.36

Find the mean of the binomial distribution for which n = 80 and p = 0.2.

• 16

• 40

• 80

• -80

A test consists of 290 true or false questions. If the student guesses on each question, what is the standard deviation of the number of correct answers?

• 8.51

• 2

• 12.04

• 3.58

Assume that male and female births are equally likely and that the birth of any child does not affect the probability of the gender of any other children. Find the probability of at most three boys in ten births.

• 0.172

• 0.300

• 0.333

• 0