AP Stats Probability Practice

In an AP Statistics class, 57% of students eat breakfast in the morning, 80% of them floss their teeth, and 46% of the students do both.  What is the probability that a randomly chosen student eats breakfast or flosses their teeth?

• 91%

• 9%

• 11%

• 34%

A fair coin has come up "heads" 10 times in a row.  The probability that the coin will come up heads on the next flip is:

• greater than 50%, it's due to happen.

• 50%

• less than 50%, since tails is happening so much.

• Can't be determined

State the addition rule of probability.

• The addition rule of probability states that the probability of the intersection of two events A and B is equal to the sum of the probability of event A and the probability of event B.

• The addition rule of probability states that the probability of the intersection of two events A and B is equal to the product of the probability of event A and the probability of event B.

• The addition rule of probability states that the probability of the union of two events A and B is equal to the product of the probability of event A and the probability of event B.

• The addition rule of probability states that the probability of the union of two events A and B is equal to the sum of the probability of event A and the probability of event B, minus the probability of the intersection of events A and B.

What is the complementary rule of probability?

• P(A)

• P(A|B)

• P(A)

• P(A and B)

If two events are mutually exclusive, what is the probability of both events occurring?

• 0.25

• 0

• 1

• 0.5

The probability of selecting a person who is born left-handed is 0.11, or about 1 in 9. This means that

• For every 9 people, exactly 1 person will be left-handed.

• As we sample more and more people, the proportion of them who are left-handed will get closer and closer to 0.11.

• A sample of 100 randomly selected people will contain exactly 11 left-handed people.

• It is almost impossible to select two people in a row who are both left-handed.

Which of the following statements illustrates the Law of Large Numbers?

• We roll a die until it lands on four. The first four occurs on the 6th roll so the probability of rolling a four is 1/6.

• A population has 9% blue-eyed people. If we sample 100 people, 9% will have blue eyes.

• A population of individuals contains 73% that can curl their tongue. The larger the sample size we select, the closer the percentage of people who can curl their tongue gets to 73%.

• In a small number of people, the proportion who have a dog is 15%. As we increase the sample size, the proportion of people who have a dog will increase from 15%.

• Flip a fair coin and record if it lands heads up. If the first flip is tails, the next flip will likely be heads to make the probability of heads equal to 1/2.

A recent poll asked respondents about their fears. One of the questions was “Are you afraid of snakes?” The table summarizes the results, categorized by gender.

If a respondent is randomly selected, what is the probability that they are either a male or very afraid of snakes?

• 90/991

• 90/474

• 317/991

• 474/991

• 701/991

A grocery store sells many different types of M&M candies. The proportions of the different types are shown in the table.

If a bag of M&M’s is selected from among all the bags the store sells, what is the probability that it is either Milk Chocolate or Peanut?

• 0.100

• 0.426

• 0.320

• 0.574

• 0.680

If you randomly select a fish from this pet store, what is the probability it is either a goldfish or a betta?

• 0.0456

• 0.10

• 0.19

• 0.29

• 0.43