Biology Notes: Graphing
Alabama Biology Course of Study Objective #1
Glencoe High School
Mrs. Meredith Barkley
Vocabulary List (Graphing)
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Data
Unit
Quantitative Measurement
Qualitative Measurement
Data Table
Column Header
Ordered Pairs
Horizontal Axis
Vertical Axis
Title
Constant
Variable
Line Graph
Pie Graph
 Students will need a basic
understand of the meaning of
each term in order to develop
the skill of organizing and
interpreting data, which is
ESSENTIAL for scoring well
on the science portion of the
ACT.
 These terms will be covered
within class discussions and
activities.
Table of Contents (Graphing)
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6.
What is data?
How should you collect data?
Why is graphing so important?
Which type of graph should I use?
How do I interpret data for potential relationships?
Graphing Checklist
1. What is Data?
 Data = information
 This may in the form of pictures, recordings, collections,
drawing, and notes…but most of the time will be a big pile
of numbers!
 Data may provides you with…
1.
2.
Quantitative Measurements: numerical information, such as
height, temperature, and mass
Qualitative Measurements: descriptive information, such as
color, texture, smell, taste, appearance
2. How should you collect data?
 You must always collect measurements using appropriate
instruments. For example, you may use a beam balance to
calculate mass, or a graduated cylinder to calculate liquid
volume.
 Remember to use metric units in science class unless told
otherwise. For example, you should measure length in its
metric unit, the meter, as opposed to feet, which you may be
more familiar with.
3. Why is graphing so important?
 What’s the big deal? Oh, nothing really… Graphing just makes life
easier and decision-making a little quicker! There are 2 basic
reasons you should learn how to construct data tables and graphs
outlined below.
1. Organization
2. Interpretation…
People may use data tables and graphs to monitor someone’s vital
signs at a hospital, make decisions about which products to sell
for their company, analyze the correlation between consumption
of certain foods with various health concerns, or designing a
new wing design for an airplane!
Remember (as previously stated) the importance that interpreting
data can have on your score on the science portion of the ACT.
4. Which type of graph should you use?
You may encounter pie graphs, line graphs, bar graphs, pictographs,
and multiple line graphs within class. While each situation may be
a little different, there are a few basic rules you can apply when
choosing the correct graph to construct from your data.
 Pie graphs should be used to represent data in the form of
percentages.
 A line graph should be used to show the change of an item over
time.
 A bar graph should be used to compare various items by the same
criteria.
 A multiple line graph can be used to compare how two different
factors changed over the course of the same experiment.
5. How do I interpret a graph for
potential relationships?
 When the two variables are said to be “directly proportional”
that means that they will both increase together or both decrease
together. This will be represented visually by a data that increases
(upward slope) from left to right.
 When two variables are said to be “inversely proportional”
that means that as one increases that the other will decrease and
vice versa. This will be represented visually by data that decreases
(downward slope) from left to right.
 Other times, there seems to be no connection between two
variables and no relationship is identified.
 Remember, these rules only apply if someone has correctly placed
the constant (independent variable) on the x-axis and the variable
(dependent variable) on the y-axis!
One More Time…How do I interpret a
graph for potential relationships?
Directly Proportional Data
Inversely Proportional Data
 Both increase or both
 As one increases, the other
decrease
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decreases and vice versa
OR
Practice Problems: Interpreting Data /
Identifying Relationships
1. What type of relationships, if any, do the following have
in common?
2. How would you label the x and y axis for each situation?
 Size of a diaper vs. total # that can fit in a trash bag
 # of absences in school vs. report card grades
 Amount of sweets consumed vs. total body weight
 Level of education vs. income
 Drug use vs. # of criminal arrests
 # of family members who smoke vs. percent chance you will also
become a smoker
Graphing Checklist
Always include the following when appropriate:
 Title
 Neat x and y-axis
 Even increments on both x and y-axis
 Label on both x and y-axis
 Units of measurement places in parenthesis
 Accurate Data
 Key
 Remember, the dependent variable belongs on the y-axis, while
the constant / independent variable belongs on the x-axis.