AP Stats Probability Practice

The probability that a randomly selected visitor to a certain website will be asked to participate in an online survey is 0.40. Avery claims that for the next 5 visitors to the site, 2 will be asked to participate in the survey. Is Avery interpreting the probability correctly?

• Yes, because 2 out of 5 is equal to 40%.

• Yes, because participants in the survey are selected at random.

• Yes, because participants in the survey are selected at random.

• No, because only 40% of all people will visit the site.

• No, because 0.40 represents probability in the long run over many visits to the site.

In a parking lot with 200 cars, 50 cars are white, 30 cars are red, and 20 cars are silver. One car will be selected at random from the parking lot. If each car in the parking has only one color, which of the following cannot be the probability that the selected car will be green?

• 0

• 0.1

• 0.2

• 0.5

• 0.6

A high school science teacher has 78 students. Of those students, 35 are in the band and 32 are on a sports team. There are 16 students who are not in the band or on a sports team. One student from the 78 students will be selected at random. Let event B represent the event of selecting a student in the band, and let event S represent the event of selecting a student on a sports team.

Are B and S mutually exclusive events?

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The table shows data that were collected from people who attended a certain high school basketball game and indicates the team each person rooted for and whether each of these people purchased food during the game. A person who attended the game will be selected at random. Which of the following correctly interprets mutually exclusive events represented by the table?

• Rooting for the home team and rooting for the away team

• Rooting for the home team and purchasing food during the game

• Rooting for the away team and purchasing food during the game

• Rooting for the home team and not purchasing food during the game

• Not rooting for the home team and not purchasing food during the game

As a promotion, the first 50 customers who entered a certain store at a mall were asked to choose from one of two discounts. The first discount choice was 20% off all purchases made that day. The second discount choice was 10% off all purchases for the week. Of those who received the discounts, 28 chose the first discount and 22 chose the second discount. One customer will be selected at random from those who received a discount. Let F represent the event that the selected person chose the first discount, and let S represent the event that the selected person chose the second discount.

Are F and S mutually exclusive events?

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Carson Cars sells hybrid and non-hybrid Kia, Toyota and Honda cars. All of the cars on the Carson Car lot were classified by make of the vehicle and whether or not it was a hybrid vehicle. The results are summarized in the table.

What is the probability that a randomly selected vehicle is hybrid or a Kia?

• 20/100

• 38/100

• 53/100

• 71/100

• 91/100

A recent poll asked respondents about their experiences with “hidden fees” associated with tickets to concerts, airlines, and sporting events. One of the questions was “When you are purchasing concert tickets online directly from the provider, how often do you end up paying more than the price you were initially shown as a result of taxes or other fees?” The table shows the set of responses, grouped by the age of the respondents. If a respondent from this survey is selected at random, what is the probability that the respondent is between 18 and 29 years old or responded “Always” to the question?

• 0.090

• 0.208

• 0.499

• 0.617

• 0.707

What is the probability that a randomly selected student is in 10th grade or plans to have a summer job?

• 22/260

• 64/260

• 140/260

• 182/260

A store owner reports that the probability that a customer who purchases a lawn mower will also purchase an extended warranty is 0.68.

Which of the following is the best interpretation of the probability 0.68 ?

• For all customers who purchase a lawn mower, 68% will also purchase an extended warranty.

• For all customers of the store, 68% will purchase a lawn mower.

• For all customers who purchase an extended warranty, 68% will use the warranty.

• From the next 25 customers, 17 will purchase an extended warranty.

• From the next 25 customers, 17 will purchase a lawn mower.

The probability that a randomly selected visitor to a certain website will be asked to participate in an online survey is 0.40. Avery claims that for the next 5 visitors to the site, 2 will be asked to participate in the survey. Is Avery interpreting the probability correctly?

• Yes, because 2 out of 5 is equal to 40%.

• Yes, because participants in the survey are selected at random.

• No, because there could be voluntary response bias.

• No, because only 40% of all people will visit the site.

• No, because 0.40 represents probability in the long run over many visits to the site.