Understanding Probability - Assignment

Which pair does not represent the probabilities of complementary events?

C.

Your teacher is giving out fruit for lunch. A paper bag contains 4 apples, 6 pears, and 8 oranges. What is the probability you will pick an orange at random? What is the complement to this event? What is the probability of the complement? Which fruit is more likely to be chosen?

A. C. B. C.

Which of the following are ways to express the same probability? Check all that apply.

A. B. D.

Which of the following events has a probability of 1? Check all that apply.

A. D. E.

Complete each statement. An event with a probability of 0 is: An event with a probability of 1 is:

A. Impossible D. Certain

Use the given formula to calculate the probability Probability = Number of desired outcomes/ Total number of outcomes You are rolling a 6-sided number cube with the numbers 1 through 6. Which of the following represents the probability of rolling an even number?

C.

Which of these values cannot represent the probability of an event happening?

D.

A bag of marbles has 5 blue marbles, 3 red marbles, and 6 yellow marbles. A marble is drawn from the bag at random. How many possible outcomes are there?

D. 14

A sock drawer contains 5 different colors of socks. It has 20 white, 10 black, 10 gray, 6 red, and 4 purple. If you reach into the drawer and choose a sock randomly, what is the probability you will get a black sock? P(black) = Number of favorable outcomes / total number of outcomes

P(black) = 1/5

What is the probability of landing on an even number? (Write your final answer as a percentage.)

P(event) = 50%

When you are determining the probability of an event, why must the probability be between 0 and 1? Explain your answer.

Sample Response: Probability is the ratio of the desired outcomes to all possible outcomes. If there are no desired outcomes, the ratio is 0 over all possible outcomes, thus 0. If the event is all possible outcomes, the ratio is all possible outcomes over all possible outcomes, thus 1.

Does choosing a blue marble represent the complement event of choosing a red marble? Explain.

Sample Response: The complementary event for choosing a red marble is choosing a blue or purple. The total number of marbles is 5. The probability of choosing a red marble is 1/5, and the complement would be 4/5. That is not the same as choosing a blue marble.

Caitlyn calculated the probability of the complement of rolling a number greater than 2 on a 6-side number cube. She made her calculation as follows. P(less than or equal to 2): Numbers greater than 2 / Number less than or equal to 2 = 4/2 Did she make an error? Explain.

Sample Response: Yes, she made an error. Caitlyn should have taken the desired outcomes, rolling a 3, 4, 5, or 6, and divided that by the total possible outcomes to get a probability of 4/6, or 2/3. She should have subtracted this probability from 1 to get the complement, which is 2/6, or 1/3.