# ACT Ch20

## 40 terms · Charts and Graphs

Three

Five

### It's best to do what when looking at a chart and graph passage?

Scan the passage, chart, and graph and go straight to the questions.

### Keep track of...?

Variables, units, and trends in charts.

Scan it.

### What is a variable?

A quantity that has some type of value.

### What are the two types of variables on the ACT?

Independent and dependent variables.

### Sometimes graphs include...?

percentages as measurements.

The wrong units.

### A conversion between..?

units sometimes has to be made.

### What are the four types of coordinate graphs?

Linear, graphs with curves, scatter diagrams, and flat lines.

### In a coordinate graph, the x-axis represents..?

the independent variable (manipulated variable)

### In a coordinate graph, the y-axis represents..?

the dependent variable (the variable affected by the change in the independent variable)

### A point on a graph represents..?

a value for the independent and dependent variable.

### When looking at graphs, remember to..?

look at what the variables are, how they're measured, and how they're related.

### Linear graph

The points follow a straight line.

### A positive linear relationship

an increase in x leads to an increase in y

### A negative (inverse) linear relationship

an increase in x leads to a decrease in y

### Graphs with curves

For every increase in x, the y-values become larger

are exponential.

### If a graph is curved, that means..?

the amount y changes with with each change in x is different at different points on the graph.

A best-fit line.

### A best-fit line on a scatter diagram means..?

The average of all the points on the graph when lined up

### Scatter Diagrams

Tells what the points would look like if they were averaged and lined up (a straight line) and how they really look on the graph (scattered)

### Flat Lines

No relationship between variables; the two elements plotted on the graph have no effect on each other

### A flat line is used to graph..?

data in which there is no change.

### When scanning a table,..?

first look at the variables.

### When scanning an illustration,..?

look at the variables.

### The second step when scanning a chart or graph passage is..?

Identify the question type.

Three

Look It Up

### Look it up questions

identify the piece of information needed.

### Look it up questions test the ability of...

understanding the figures.

Why?

### Why questions..

have a slightly deeper understanding of the passage.

Generalization

### Generalization questions...

presented with new situation and asked to apply the concepts provided in the passage.

Guesstimate

### Interpolation

To estimate values on a graph between two known values

### Extrapolation

To project or expand known data into an area not known