Chapter 5 Test Review Statistics

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last 6 days or less?

• 68%

• 34%

• 16%

• 2.5%

Given a mean of 75 and a standard deviation of 7, what percentage of scores are above 82?

• 34%

• 81.5%

• 16%

• 2.5%

The probability that an American household will have at least 2 cars is...

• 0.55

• 0.35

• 0.45

• 0.93

What's the expected number of cars in a randomly selected American household?

• 1.00

• 1.75

• 1.84

• 2.00

How would you interpret the expected value in number 3?

• The maximum number of cars for the household is Exp(C).

• The average number of cars for the household is Exp(C).

• If we randomly select many households, the average number of cars per household will be approximately by Exp(C).

• If we randomly select many households, the average number of cars per household will vary approximately by Exp(C).

The standard deviation of X is o_x = 1.08. If many households were selected at random, which of the following would be the best interpretation of the value 1.08?

• The mean number of cars would be about 1.08.

• If we randomly selected many households, the number of cars would typically vary be about 1.08 cars from the mean.

• The number of cars would be at most 1.08 from the mean.

• The number of cars would be within 1.08 from the mean about 68% of the time.

• The mean number of cars would be about 1.08 from the expected value.

The number of calories in a 1-ounce serving of a certain breakfast cereal is a random variable with mean 110 and standard deviation 10. The number of calories in a cup of whole milk is a random variable with mean 140 and standard deviation 12. For breakfast, you eat 1 ounce of the cereal and 1/2 cup of whole milk. Let T be the random variable that represents the total number of calories in this breakfast. The mean of T is...

• 110

• 140

• 180

• 195

The number of calories in a 1-ounce serving of a certain breakfast cereal is a random variable with mean 110 and standard deviation 10. The number of calories in a cup of whole milk is a random variable with mean 140 and standard deviation 12. For breakfast, you eat 1 ounce of the cereal and 1/2 cup of whole milk. Let T be the random variable that represents the total number of calories in this breakfast. The standard deviation of T is...

• 22

• 16

• 15.62

• 11.66

It turns out that 25 seniors at Fashionable High School took both the AP Statistics exam and the AP Spanish Language exam. The mean score on the Statistics exam for the 25 seniors was 2.4 with standard deviation of 0.6, and the mean score on the Spanish Language exam was 2.65 with a standard deviation of 0.55. We want to combine the scores into a single score. What are the correct mean and standard deviation of the combined scores?

• 5.05; 1.15

• 5.05; 1.07

• 5.05; 0.66

• 5.05; 0.81

• 5.05; You cannot determine the standard deviation from this information.

Which of the following is a discrete random variable?

• I only

• II only

• III only

• I and II

• II and III