Apply the Addition Rule and Multiplication Rule to Calculate Probabilities

The formula for finding “or” probabilities is called the _______________________ Rule.

• Addition

• Subtraction

• Multiplication

• Division

Which of the following is the correct statement of the Addition Rule?

• P(A or B) = P(A) ꞏ P(B) – P(A and B)

• P(A or B) = P(A) + P(B) + P(A and B)
  

• P(A or B) = P(A) + P(B) – P(A and B)

• P(A or B) = P(A) ꞏ P(B) + P(A and B)

A homeroom contains 25 students. 15 are on the honor roll and 12 work after school. 7 very busy students are on the honor roll and work after school. Suppose you pick a student at random from this homeroom. What is the probability that they are on the honor roll or work after school?

• 74%

• 14%

• 28%

• 80%

Charles surveyed ten of his friends and asked them two questions. “Do you drive a Ford?” and “Do you drive a pickup truck?” The results are shown in the table. Let Event P = a person picked at random from this sample owns a Ford and Event F = a person picked at random from this sample owns a pickup. Find P(F or P) [Express your answer as a whole number followed by the "%" sign.]

(a)  

What is the Multiplication Rule?

P(A ∩ B) = ​ (a)  

• P(A) ⋅ P(B|A)

• P(A) - P(B)

• P(A) ⋅ P(B)

• P(A) + P(B) - P(A ∩ B)

Using the multiplication rule, what is the probability of drawing two aces in a row from a deck of 52 cards, without replacement?

What is the Multiplication Rule?

• P(A) ⋅ P(B|A)

• P(A) - P(B)

• P(A) ⋅ P(B)

• P(A) + P(B) - P(A ∩ B)

Consider the table shown. It records the results of a survey of doctors. If you pick a doctor at random from the set represented by this table, find the probability that the selected doctor is either male or a specialist.

• 65.2%

• 80%

• 20%

• 34.8%

Consider the table shown. It records the results of a survey of doctors. If you pick a doctor at random from the set represented by this table, find the probability that the selected doctor is either female or a non-specialist.

• 65.2%

• 80%

• 20%

• 34.8%

Consider the Venn Diagram shown. It is the same one from earlier, but now consider a trial that consists of selecting two students from the set at random and without replacement. To the nearest tenth of a Percent, find the probability that either the first student or the second student selected is a Freshman.

• 86.7%

• 84.0%

• 66.7%

• 64%