ap statsistics probability and random variables

Choose the correct examples of discrete variable.

• A film critic's rating of a film (0 - 4 stars)

• Time taken to commute to work

• The sum of the numbers rolled on a pair of dice

• Winning ticket number drawn from a raffle

• Amount of gasoline a car

Eva flips a coin. If she gets heads, she wins $4. If she gets tails, she loses $3. What is her expected value of a coin flip?

• $1

• $0.50

• - $0.50

• $0

The table above shows a television station's advertisement sales. The distribution of sales for one 24-hour day is given. Solve for the standard deviation. Round to the nearest hundredth.

• 35.76

• 268.1

• 16.3

• 1279.35

The table above shows the number of cell phones per household in a small town. Find the mean round to the nearest hundredth.

• 2.80

• 2.93

• 0.10

• 0.14

The mean hourly salary for a high school graduate (H) is $13.50 per hour with a standard deviation of $5.75. The mean hourly salary for a person with an Associate's degree (A)is $19.75 with a standard deviation of $9.25. What is expected difference in the hourly salaries between a high school graduate and a person who earned an Associate's degree? D = H - A.

• $33.25

• $-3.50

• $-6.25

• $15.00

• .22

• .64

• .36

• .78

A marketing survey compiled data on the number of cars in households.  If X = the number of cars in a randomly selected household, and we omit the rare cases of more than 5 cars, then X has the following probability distribution: 

X           0          1          2          3           4           5  

P(X)   0.24    0.37    0.20    0.11    0.05     0.03

What is the probability that a randomly chosen household has at least two cars?

• 0.20
• 0.29
• 0.39
• 0.61

Classify.

The numbers of cheeseburgers a fast-food restaurant serves each day

• None of these

• Abstract

• Continuous

• Discrete

Determine the standard deviation of the distribution.

• 2.84

• 3.08

• 3.21

• 3.80

Lilah flips a coin, and considers "tails" a success. How to find the probability that the coin comes up with the first tails in fewer than 5 flips?

• geometcdf(1/2, 5)

• geometpdf(1/2, 5)

• geometcdf(1/2, 4)

• geometpdf(1/2, 4)