Steps in Constructing a Line Graph
Graphs show the relationship between the variables. Graphs show how the
dependent variable has changed. They may show a pattern.
Step
1
2
3
4
What to do
How to do it
Identify the variables Independent variable: manipulated
(deliberately chosen) by the experimenter.
• Label this on the x-axis (horizontal
axis).
• It should be the first set of data in a
data table.
Label each axis
Determine the
variable range
Dependent variable: responding (changes)
because of the independent variable.
• Label this on the y-axis (vertical axis).
Each axis must be labeled with the variable
name and unit. The unit is always in
parenthesis.
Variable (unit)  time (seconds)
For each variable, subtract the lowest value
from the highest value. This number is your
RANGE.
x-axis range:
y-axis range:
Number (scale) each For each axis, divide the range and the
axis
number of squares on the axis. Then round to
a number that is easy to count by such as 1,
2, 5, 10, 20, etc. Each axis must be done
separately.
Your first axis number should be below your
lowest data value and countable by the
number you choose from above.
Example:
Data values: 11, 13, 19, 24, 27, 33
Range: 33 – 11 = 22 Squares = 12
22 ÷ 12 = 1.8, so choose to count by 2’s
starting at the number 10 and going up to 34.
5
Plot the data points
Plot each ordered pair on the graph with a
small dot.
You numbered your graph correctly if your
data points cover more than half of the graph.
6
Draw the line
7
Title the graph
8
Interpret the graph
For additional data sets, use another symbol
and include a key on the graph.
Draw a line or curve connecting the data
points.
Give your graph a descriptive title using the
following format:
dependent variable vs. independent variable
Child’s Height vs. Child’s Age
Describe the relationship between the
independent variable and the dependent
variable.
As the independent variable increases, the
dependent variable (increase, decreases, is
constant).
As the child’s age increases, the child’s
height increases.
Types of relationships (trend patterns) of line graphs:
Direct (positive): As the independent
variable increases, the dependent variable
increases.
Inverse (indirect): As the independent
variable increase, the dependent variable
decreases.
Cyclic: As the independent variable
increases, the dependent variable
increases & decreases in a regular
pattern.
Static (constant): As the independent
variable increases, the dependent variable
stays the same.