The document discusses different types of graphs used to display and analyze data. It describes line graphs as used to show relationships between two quantitative variables, such as speed vs engine size. Bar graphs are used to show one qualitative variable and one quantitative variable, like migration distance of different bird species. The document provides instructions on how to create line graphs and bar graphs, including labeling the axes, plotting data points, and connecting points for line graphs. It emphasizes examining the graph to understand trends in the data and relationships between variables.

1. Graphing Data

2. Displaying and Analyzing Data
The best method for displaying and analyzing data is
through the use of graphs
Graphing is an important procedure used by scientists to
easily compare multiple variables.
There are many types of graphs, but the three most
common kinds are line graphs, bar graphs, and pie charts
-- In this class, we will be primarily using line graphs
and bar graphs
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3. What type of graph?
• You may wonder; How do I know which
type of graph to use?
– Line graphs out now!!just for time graphs!!!
Find are not Click Here!
– Use a line graph when you have 2 quantitative
(number) variables
• Ex. Speed vs. engine size
– Use a bar graph when you have one qualitative
variable and one quantitative variable
• Ex. Migration distance vs. bird species

4. Creating a Graph
y
• Draw and label the x-axis and the
y-axis
-- the x-axis is the horizontal
axis and the y-axis is the
vertical axis
8. Label what variable is on each
axis
-- the independent
(manipulated) variable always
x
goes on the x-axis and the
dependent (responding) Independent Variable
variable always goes on the
y-axis

5. Creating a Graph
1. Decide which intervals you will be using on each axis and
write those in
– Be sure that the intervals are appropriate for your graph
• Ex. 1 – If your dependant variable has values ranging from 5cm to 600cm, an interval of 5cm
might not be enough
• Ex. 2 – If you are measuring the growth of a plant each week, you shouldn’t use meters on your
graph
y
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6. Creating a Graph
1. Plot the data points that you collected on the graph.
2. If the graph is a line graph, connect the points with as
smooth a line as possible.
3. Give your graph a title
– Usually, the title of a graph is similar to the variables being manipulated and
y
measured.
Bob’s Weight Change Over Time
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7. Graphical Analysis
• Remember that the reason for creating
graphs is to help us to better visualize
what has occurred.
– You should always look at your graph after
you make it and consider what it is telling you
• What is the general trend in the data? What is the
relationship between the variables? Does it make
sense?
Final Questions

8. Question 1
• You run an experiment to test how the
brand of gasoline used effects your cars
gas mileage. When you graph the data:
– What type of graph would you make?
Bar Graph – brand is a qualitative variable, mileage is quantitative
Answer
– Which variable would go on the x-axis? Why?
The brand would go on the x-axis because it is the independent variable
Answer
– Which variable would go on the y-axis? Why?
The mileage would go on the y-axis because it is the dependant
Answer
variable

9. Question 2
• You measure the height of everyone at
GM and create a graph of average height
for each age from 14 to 18
– What type of graph should this be?
This should be a line graph because both variables are quantitative
Answer
– What trend do you expect to see in the data?
The graph should have a positive (upward) slope. As students get older
Answer
you would expect their heights to increase.
Remember to write out 2-5 questions about
the notes for class!!