1. Graphing AP Biology

2. Use Computer Software
Excel

3. Components Title Each line or bar must be easily identifiable
Informs the reader about the experiment and tells the reader exactly what is being measured
Each line or bar must be easily identifiable
Axes must be clearly labeled with units
X axis shows the independent variable
Y denotes the dependent variable
Example: time, light intensity, concentration of a hormone or nutrient
DRY MIX = dependent responding on y axis
manipulated independent on x axis
independent (IV) = what I the scientist manipulated
dependent (DV) = responds according to changes made to the independent variable

4. Component Intervals must be uniform
If one square on the x axis equals five minutes, each interval must be the same and not change to 10 minutes or one minute.
If there is a break in the graph such as a time course over which little happens for an extended period, it should be noted with a break in the axis and corresponding break in the data line.
It is not necessary to label each interval. Labels can identify every 5 or 10 intervals as appropriate
Labels on the x and y axis should allow the reader to easily see the information.

5. Components
More than one condition of an experiment may be shown on a graph by the use of different lines.
Ex: products in an enzyme reaction at different temperatures can be compared on the same graph. Each line must be clearly diffrentiated from the others by label, different style or colors indicated by a key to aid in comparing the results.

6. Components Clarify if the data starts at the origin (0,0) or not.
The line should not be extended to the origin if the data do not start there!
The line should not extend beyond the last data point (extrapolation) unless a dashed line clearly indicates that this is a prediction about what may happen.

7. Components Error Bars Included in most graphs
For counted, measured data
Shows standard error (SE)
Do not use standard deviation on bar graphs
Can be used on scatter plots
of means

8. Components
How to create error bars

9. Types of Graphs Scatterplots
Comparing one measured variable against another
Looking for trends or associations
Plot of individual data points
If the relationship is thought to be
linear to see corelation
Find by linear regression
Draw a line showing pattern
Draw a line connecting all

10. Types of Graphs Bar Graph Comparison of populations Measured variables
Ex: compare spine length with and without preditors, shape of leaves in or out of sun
Measured variables
Must include standard error

11. Types of Graphs Scatterplots continue
Plot of manipulated independent x variable against the dependent y variable
General shapes/trends=biological implications
Bell curve: random samples or normal distributions
Concave upward curve: exponential increasing function (early stages of bacterial growth)
Sine wave: biological rhythm

12. Types of Graphs
Box and Whiskers

13. Types of Graphs
Hystograms

14. Source College Board Quantitative Skills Guide page 6-14