# Variables & Patterns I

### Study Guide Review

## Unit Description

In this unit students develop the ability to look for quantities that change over time, especially distance and speed of moving objects, and their ability to construct and interpret data tables and coordinate graphs representing patterns in that change. Students will also extend their understanding and skill in working with relationships between quantitative variables as they are expressed in written stories, tables, and graphs. The focus is on cause-and-effect relationships where changes in one variable can reasonably be thought to cause changes in another.

## Which one goes where?

**Independent Variable:**(X-Axis) a variable whose value determines the value(s) of other variables

**Dependent Variable: **(Y-Axis) a variable that depends on one or more variables

## The Coordinate Plane, Grid, & Graph

## The Important Parts

**1. X-Axis:**a horizontal line on the coordinate grid (left or right)

**2. Y-Axis: **a vertical line on the coordinate grid (up or down)

**3. Quadrants: **four sections that divide the coordinate grid (I, II, III, IV)

**Plotting Points: **When plotting points on the coordinate grid you must plot the x-coordinate and then the y-coordinate. You can think of it as walking into an elevator (move left or right along the x-axis) and traveling to a certain floor (move up or down on the y-axis).

## Graphing

## Steps

When graphing data on the coordinate grid, you need to include the following:

- Identify the
**independent variable**(x-axis) and**dependent variable**(y-axis) - Write appropriate
**labels**on the x-axis and y-axis - Choose an appropriate
**scale**or**intervals**for the x-axis and the y-axis - Plot the
**points**on the graph (x, y)

## Story Graphs

## How do I read this story?

**READING **

1. Read the title and the labels on the x-axis and the y-axis

2. Observe the lines on the graph

- Long, Steep Line = Fast increase or decrease
- Short, Shallow Line = Slow increase or decrease
- Line Pointing Up = Increasing
- Line Pointing Down = Decreasing
- Straight Horizontal Line = Stays the same
- Diagonal Line = Constant, steady rate

**DRAWING**

1. Read the scenario

2. Search for clue words in the story

- Increasing = Line pointing up
- Decreasing = Line pointing down
- Quickly, Rapidly = Steep line
- Slowly = Shallow line
- Constant, Steady Rate = Diagonal line increasing or decreasing
- Stays the Same = Straight horizontal line