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Clarifications: Each clarification provides an explanation of the indicator/objective to help teachers better understand the concept. Classroom examples are often included to further illustrate the concept. While classroom examples could be shared with the students, the intended audience for the explanation/clarification is the classroom teacher-not the student. In addition, classroom examples may or may not reflect the assessment limits.

Standard 5.0 Knowledge of Probability

Topic B. Theoretical Probability

Indicator 1. Determine the probability of one simple event comprised of equally likely outcomes

Objective a. Make predictions and express the probability as a fraction

Assessment limit: Use a sample space of no more than 20 outcomes

Clarification

Probability is the chance or likelihood of an event occurring. Theoretical probability determines the chance of an event occurring based on the ratio of the favorable outcomes to the total number of outcomes. When drawing playing cards from a deck that contains only hearts, there are 13 possible cards that can be drawn. An event is a specific set of outcomes, such as drawing a face card.

A favorable outcome is one of the possible outcomes and is part of the event for which we want to find the probability. Drawing a king is a favorable outcome in the set of outcomes drawing a face card.

Classroom Example 1

When drawing cards from a deck that contains only hearts, there are 13 possible outcomes. The probability of drawing a face card (King, Queen or Jack) is 3 out of 13 or there is a 3/13 chance that you will get a face card when you draw a card from this deck.

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What is the probability of drawing a card less than a 6, if an ace is the highest card? 4/13

Classroom Example 2

A bag contains 12 marbles (4 red, 4 blue, 4 green).

  • What is the probability of picking a red marble? 4/12
  • What is the probability of picking a red marble or a blue marble? 8/12

Clarification about the assessment limit:
The difference between 4th and 5th grade is the assessment limit. Fourth grade has an assessment limit of 6 outcomes such as rolling a die or using a spinner with 6 equal-sized spaces. 5th grade has an assessment limit of 20 outcomes, which allows considerable problem extension. For example, activities can include picking a marble from a bag of 20 marbles or using one suit from a deck of cards and choosing a specific card.
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Resources for Objective 5.B.1.a:
CLARIFICATIONS | Sample Assessments |