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Creating Probability Models

Answer Keys Here

Aligned To Common Core Standard:

Grade 7 Statistics - 7.SP.C.7

What are probability models? When you enter the mathematical world, you will find mathematics filled with concepts and mathematical models. A very well-known model in mathematics that a lot of you may find difficult is the probability model. This model is precisely a mathematical illustration of a random phenomenon. Defined by its sample size, it has different events occurring in its sample space with probabilities associated with each event. The set of sample space S denotes all the possible outcomes for a probability model. Consider this example: In a bowl of five marbles, that has one red, one blue, one yellow, one green, and one lavender. If you are required to pick a random marble out of the bowl, the possible outcomes would be S = {red, blue, yellow, green, lavender}. If 3 are red and 2 are blue then the sample space S would be {red, blue}. Since only two possible color outcomes are possible, the probability would be 50% in this case. There are two basic rules of probability. Rule 1: The probability P(A) is any number between 0 and 1. Rule 2: The probability is equal to 1; [P(S) = 1] This series of worksheets and lessons will help students learn to model and represent random phenomenon and predict all possible outcomes of and event.

Printable Worksheets And Lessons

Homework Sheets

Oddly enough the more difficult problems are found on page 1. The other pages are more common.

  • Homework 1 - On the last day of a Shakespeare class, an English teacher asked her students which play they liked the most. Out of the 20 students, 4 liked Julius Caesar best.
  • Homework 2 - What is the probability of getting brown? Write your answer as a percentage?
  • Homework 3 - There are 10 pieces of fruit in a basket, including 3 oranges. What is the probability that a randomly selected piece of fruit will be an orange?

Practice Worksheets

This is the first time that students are looking at probabilities.

  • Practice 1 - Terence organizes a small party. There are 50 glasses of fruit juice at the party, 15 of which contain apple juice. What is the probability that a randomly selected drink will be apple juice?
  • Practice 2 - Lee has a fruit basket. The baskets contain 8 pomegranates and 10 oranges. Without looking, if Lee chooses a fruit from the basket, what is the probability that it will be an orange?
  • Practice 3 - Eva has a box that contains stones. There are 60 stones in the box. 20 of the stones are red. What is the probability that a randomly selected stone will be red?

Math Skill Quizzes

I used notation for find probabilities in here, just in case it appears on a standardized test.

  • Quiz 1 - A bag contains 13 purple and 16 blue marbles. A marble is drawn at random. Probability (purple).
  • Quiz 2 - Jerry is watching animals at the zoo. He sees 5 bears out of a total of 20 animals. What is the probability that the next animal Jerry sees will be a bear?
  • Quiz 3 - Anna has a school bag. She has 8 books, of which 3 are math books. What is the probability that a randomly selected book will be a math book?