14.2 Introduction to probability

Suppose you roll a 4-sided die , which gives equal probabilities of rolling 1, 2, 3, or 4. (*Yes, these really do exist.)

• A

  What is the probability that you will roll a 3?

• B

  Explain, in your own words, what your answer to part (a) means. Do not use the words “probability” or “chance.” A typical 9-year-old should be able to understand your explanation.

• C

  What is the probability that you will roll an even number?

• D

  What is the probability that you will roll a number less than 3?

• E

  What is the probability that you will roll a number less than 4?

• F

  What is the probability that you will roll a number less than 7?

Suppose you roll two 4-sided dice .

• A

  Draw a tree diagram showing all the possible outcomes for both rolls.

• B

  What is the probability that you will roll “3 on the first die, 2 on the second?”

• C

  What is the probability that you will roll “3 on one die, 2 on the other?”

• D

  What is the probability that the sum of both dice will be a 5?