Addition Rule

Front

What is the Addition Rule in probability?

Back

The Addition Rule states that the probability of the occurrence of at least one of two events is the sum of their individual probabilities minus the probability of their intersection.

Front

How do you calculate the probability of drawing a spade or a red card from a standard deck?

Back

P(spade or red) = P(spade) + P(red) - P(spade and red) = 13/52 + 26/52 - 0 = 39/52.

Front

What does it mean for two events to be mutually exclusive?

Back

Two events are mutually exclusive if they cannot occur at the same time.

Front

If you roll a die, what is the probability of rolling an even number or a 5?

Back

These events are mutually exclusive, so P(even or 5) = P(even) + P(5) = 3/6 + 1/6 = 4/6.

Front

What is the formula for calculating the probability of either event A or event B occurring?

Back

P(A or B) = P(A) + P(B) - P(A and B).

Front

In a survey, if 31% own an SUV and 74% own a car, how do you find the probability of owning either?

Back

Use the Addition Rule: P(SUV or car) = P(SUV) + P(car) - P(SUV and car) = 0.31 + 0.74 - 0.10 = 0.95.

Front

What is the probability of drawing a heart or a diamond from a standard deck?

Back

P(heart or diamond) = P(heart) + P(diamond) - P(heart and diamond) = 13/52 + 13/52 - 0 = 26/52.

Front

If two events are not mutually exclusive, what must you do when calculating their combined probability?

Back

You must subtract the probability of their intersection.

Front

What is the probability of spinning an odd number or an 8 on a spinner numbered 1-8?

Back

These events are mutually exclusive, so P(odd or 8) = P(odd) + P(8) = 4/8 + 1/8 = 5/8.

Front

What is the probability of drawing a face card or a red card from a standard deck?

Back

P(face or red) = P(face) + P(red) - P(face and red) = 12/52 + 26/52 - 6/52 = 32/52.