AP Statistics: Probability, Random Variables, and Probability Distributions Practice Test

What is the probability that a randomly selected girl speaks French?

In your top dresser drawer are 6 blue socks and 10 grey socks, unpaired and mixed up. One dark morning you pull two socks from the drawer (without replacement, of course!). What is the probability that the two socks match?
Hint: try a tree diagram, but be careful with probabilities on the second column of branches

If P(A) = 0.24 and P(B) = 0.52 and A and B are independent, what is P(A or B)?
Hint: Use formula card

Event A occurs with probability 0.2. Event B occurs with probability 0.8. If A and B are mutually exclusive (disjoint), then…

If 10 is added to every value in a set of data, what will happen to the value of the mean?

If 10 is added to every value in a set of data, what will happen to the value of the standard deviation?

In a survey of men in the United States (ages 20-29), the mean height was 69.6 inches with a standard deviation of 3.0 inches. Find the minimum height in the top 22%.

The mean number of accidents a week at a company is 6.4 with a standard deviation of 1.5. What proportion of weeks would you expect to have less than 5 accidents?

95% of students at school weigh between 62 kg and 90 kg. Assuming this data is normally distributed, what are the mean and standard deviation

 Jen’s commute to work requires that she take the Blue subway line, then transfer to the Red line. The length of the trip on the Blue line has a mean of 18 minutes with a standard deviation of 2 minutes. The Red line trip takes 12 minutes with a standard deviation of 1 minute. The waiting time between when she gets off the Blue line and her Red line train arrives has mean of 10 minutes and a standard deviation of 5 minutes. Assume (perhaps unrealistically) that these times are independent random variables. What are the mean and standard deviation of her entire commute?

Which of the following is NOT a discrete random variable?

Police estimate that 85% of drivers do not text and drive. They set up a safety roadblock at a busy intersection to check for this infraction. What is the probability that the first texter is in the thirteenth car stopped?

During a week’s worth of soccer practice, a player practices total free kicks and
has a chance of scoring. What is the probability that he or she scored at least
times? Assume each shot is independent.

Suppose you are throwing three darts and you have a one third chance of hitting the bull’s eye. Each throw is independent of one another. What is the chance of hitting the bull’s eye at least once?

A particle travels left with probability one sixth and right with probability five sixths. Each movement is independent of the others. What is the chance that after three movements, the particle ends up one unit to the right?

Which of the following is a discrete random variable?

Let us suppose you are a waiter. You work your first four shifts and receive the following in tips: (1) 20, (2) 30, (3) 15, (4) 5. What is the mean amount of tips you will receive in a given day?

Which of the following would be considered a binomial experiment?