Skip to content

Grade 8 - Claim 1 - Target F

Back to Results

Mathematics

Target F

Use functions to model relationships between quantities

Sample Item

Grade 8

Test

Claim 1

Concepts and Procedures

Students can explain and apply mathematical concepts and carry out mathematical procedures with precision and fluency.

Grade

Grade 8

Content Domain

Functions

Standards

F-4F-5

Standards

  • F-4

    Construct a function to model a linear relationship between two quantities. Determine the rate of change and...

  • F-5

    Describe qualitatively the functional relationship between two quantities by analyzing a graph (e.g., where the function...

Clarifications

Tasks for this target will ask students to construct a function to model a linear relationship between two quantities and determine the rate of change or initial value of a linear function from given...

Range Achievement Level Descriptors

Evidence Required

  • 1

    The student constructs a function to model a linear relationship between two quantities.

  • 2

    The student determines the rate of change and initial value of a function, either from a description of a relationship or from two (x, y) values, including reading the rate of change...

  • 3

    The student interprets the rate of change and the initial value of a linear function in terms of the situation it models, its graph, or a table of values.

  • 4

    The student qualitatively describes the functional relationship between two quantities by analyzing a graph (e.g., whether the function is increasing or decreasing, or whether the graph is linear or nonlinear).

  • 5

    The student draws a graph that exhibits the qualitative features of a function that has been described in writing.

Item Guidelines

Depth of Knowledge

  • M-DOK1

    Recall includes the recall of information such as fact, definition, term, or a simple procedure, as well as performing a simple algorithm or applying a formula. That is, in mathematics a one-step, well-defined, and straight algorithmic procedure should be...

  • M-DOK2

    Skill/Concept includes the engagement of some mental processing beyond a habitual response. A Level 2 assessment item requires students to make some decisions as to how to approach the problem or activity, whereas Level 1 requires students to demonstrate a...

Allowable Item Types

  • Equation/Numeric
  • Matching Tables
  • Multiple Choice, single correct response
  • Graphing

Allowable Stimulus Materials

Graphs, equations, tables, written descriptions

Key/Construct Relevant Vocabulary

Function, slope, y–intercept, linear, nonlinear, rate of change, increasing, decreasing, constant, interval, relation

Allowable Tools

Calculator

Target-Specific Attributes

None

Accessibility

Item writers should consider the following Language and Visual Element/Design guidelines [1] when developing items. Language Key Considerations: Use simple, clear, and easy-to-understand language needed to assess the construct or aid in the understanding of the...

Development Notes

Function notation is not required in Grade 8. Items and tasks developed for the Grade 8 Function domain should not use formal function notation [i.e., f(x)]. [1] [1] Items that use function notation may appear...

Task Models

Task Model 1

  • Item Types

    Equation/Numeric
  • Depth of Knowledge

    M-DOK2
  • Standards

    F-4

Target Evidence Statement

  • The student constructs a function to model a linear relationship between two quantities.

  • Allowable Tools

    Calculator

Task Description

Prompt Features: The student is prompted to construct a linear function given a linear relationship between two quantities. Stimulus Guidelines: Tables should be labeled. Graph scale should contain only integers. Context should be familiar to students 13 to...

Stimulus

The student is presented with a table of input and output values, a graph, or a verbal statement that represents a linear function.

Example 1

Example Stem 1: This table of values represents a linear function.

x y
2 –6
3 –6.5
8 –9

Enter an equation in the form y = mx +b that represents the function.

Rubric: (1 point) Student enters the correct equation (e.g., y = – 0.5x – 5).

Example 2

Example Stem 2: This graph represents a linear function.

A coordinate grid is shown with x and y axes ranging from negative 6 to 6. Two points are shown on a line at (0, 2) and (1, negative 2).

Enter an equation in the form y = mx +b that represents the function.

Rubric: (1 point) Student enters the correct equation (e.g., y = – 4x + 2).

Example 3

Example Stem 3: A swimming pool with 1600 gallons of water is emptied at a constant rate of 300 gallons every 2 hours.

Enter an equation in the form y = mx +b that represents the amount of water y, in gallons, remaining in the pool after x hours.

Rubric: (1 point) Student enters the correct equation (e.g., y = – 150x + 1600).