School Improvement in Maryland
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. Identify the probability of one simple event

Objective a. Describe the probability of an event using words

Assessment limit: Use probability terms of more (or most) likely, less (or least) likely, or equally likely

Clarification
Probability is the area of mathematics that measures how likely it is for an event to occur. Theoretical probability determines the chance an event will occur based on possible outcomes. An outcome is a result. For example, when flipping a coin, there are two possible outcomes (heads, tails). Or, when rolling a number cube, there are six possible outcomes (1, 2, 3, 4, 5, and 6). An event is a specific outcome that may or may not happen, such as flipping a heads, or rolling a 3.

  • If the chances that something will happen are equal, we say they are equally likely. For example, if a spinner is divided into 8 equal sections (see spinner A), then the chance of landing on each section is equally likely. Moreover, since 4 sections are red and 4 sections are blue, the chance of landing on red is equally likely to the chance of landing on blue, and vice versa.

  • If the chances are greater that something will happen then we say that it is more likely. For example, if a spinner is divided into 8 equal sections with 4 sections red, 2 sections blue, and 2 sections yellow (see spinner B), the chance of landing on red is more likely than landing on blue. Also, landing on red is more likely than landing on yellow. However, the chance of landing on red is equally likely to landing on blue and yellow combined.

  • If the chances are less that something will happen then we say that it is less likely. For example, if a spinner is divided into 8 equal sections with 3 sections blue, 3 sections yellow, and two sections red (see spinner C), the chance of landing on red is less likely than landing either on blue or on yellow.

Classroom Example 1

pie charts
/instruction/clarification/mathematics/grade3/xml/5B1a.xml
Resources for Objective 5.B.1.a:
CLARIFICATIONS | Thinking Skills | Sample Assessments |