AP Biology Summer Graphing Assignment 2024-25

Dear AP Biology Students:

DUE: First class period of AP Biology

Materials Needed: a printed copy of this assignment, a pencil and a straight edge

Time Required: Probably 1-3 hours

Graphing plays a major role in AP biology. Most students think they know how to graph because they have

graphed a lot in math classes. Past experience has indicated that this is a false sense of knowledge since

oftentimes one can use a graphing calculator or plots on graph paper with axes and scaling already on the

graph. In AP Biology you will almost always be given a blank graph and will have to determine the proper size,

scaling and axes for the graph you will be plotting. Points are often awarded for

1. correct scaling (Proper spread of axis numbers and the use of most of the graph)

2. correct labeling of axes with units

3. correct plotting of data points

4. sometimes you may get a point if the graph is properly titled

Please read through the following and then print out the exercise so that you can practice doing the graphs.

This assignment is due on the first day of school.

If you get stuck, please email me and I shall reply as soon as possible.

Happy graphing.

Name: AP Bio Graphical Practice Assignment

Science Practice 4: Representing and describing data

Representing and describing data is one of six major practice skills that you will need to learn for the national

exam.

You must know how to construct and interpret the following graph types:

1. X,Y 3. Bar 5. Line 7. Box & Whisker

2. Log Y 4. Histogram 6. Dual Y 8. Pie

For each of the above you should be able to construct a graph showing the following.

A. orientation C. units E. plotting data points

B. axis labeling D. proper scaling F. trend line (for above graphs 1,2 5,6 only)

Let’s learn about each graph type and then practice constructing some of them.

1. X, Y Graph:

This is your standard graph with the independent variable

(what you change in experiment, often a unit of time)

on the X-axis and the dependent variable

(what you measure in an experiment) on the Y=axis.

An example is at right.

2. Log Y graph:

This graph is similar to the X,Y graph except the Y axis is a

logarithmic scale. Note line spacings: separation decreases

as one goes up the Y axis

3. Bar Graph:

A graph showing the numerical value of a variable as the height or length of a rectangle representing

categorical (nonnumerical) data. Note that the categorical data can be on the horizontal or vertical axis.

4. Histogram:

A histogram is like a bar graph except that the data is noncategorical and continuous (think distribution)

and that the rectangles are placed side-by-side. A histogram represents the frequency distribution of

continuous variables. Conversely, a bar graph is a diagrammatic comparison of discrete variables.

A histogram presents numerical data whereas a bar graph shows categorical data.

The histogram is drawn in such a way that there is no gap between the bars.

5. Line Graph:

A line graph consists of a series of points

plotted on the grid and connected point

to point by a line. Line graphs are only

used when both variables are quantitative.

Line graphs show trends, such as how

things change over time. See the example

at right. Lines should start and end on dots!

Do not draw the line past a dot unless asked

to extrapolate.

6. Dual Y Graph:

A graph showing two dependent variables (Y-axes) for the same independent variable (x-axis). The

Y-axes are placed at opposite ends of the X-axis and scaled and labeled independently.

7. Box and Whisker Graph:

A graphic way to display the median, quartiles, and extremes of a data set on a number line to

show the distribution of the data.

8. Pie Graph:

A special chart that uses "pie slices"

to show relative sizes of data. The

chart is divided into sectors, where

each sector shows the relative size

of each value. The total equals 100%.

Basic Graphical Elements:

1. Axis labels: You plot the independent variable (the one which you control, the inputs) on the horizontal axis

(x-axis) and the dependent variable (the one you are measuring, the outputs) on the vertical axis (y-axis).

Include a short descriptive label that represents each axis. ex. length of tails (cm)

2. Units: Write the units in parenthesis after the axis label—often this is an abbreviation. ex. (cm)

3. Intervals/Scaling: Choose uniform intervals that make it easy to read so the data occupy most of the graph.

You can include a break in the axis if there is a large gap between zero and the data points. Be careful not to

exaggerate the variations in the data if you do this. Many students have difficulty here!

4. Data: Plot the data points on the graph. You do not normally connect the dots. You may connect the dots

but make sure the line starts and stops on a dot! Decide whether the origin (0,0) is a valid data point. If the

data points show a correlation you may add a trend line (line of best fit) or a smooth curve that represents the

overall pattern. If it’s linear, this typically can be added by using a ruler and “eyeballing” it. A trend line is a nice

way to illustrate the basic relationship between the two variables. You may need to find the equation of the

trend line. NOTE: The “rate” of some reactions or process is the slope of the line!

5. Title: Choose a title for the graph that uniquely identifies it. The title should not just repeat the labels but

add information specific to what the data represents. The title informs the reader about the experiment and

tells the reader exactly what is being measured.

It is Practice Time! Correctly construct graphs and interpret data asked below.

Title:

I. Following a flu outbreak, a student gathered data on the number of students who became ill until

she became sick on the 14th day of her study. The information she gathered is shown below.

Create a line graph of the data below on the graph above. Be sure to scale the graph properly.

1. On what day/date were the most students ill? __________

2. Between which two days was the rate of reported illnesses the greatest? __________

3. What was the greatest number of students ill on any one day? __________

4. Estimate the probable number of students who might report to be ill on day 15 if the trend continues.

__________

II. In 1989, the US Department of the Interior reported that there were 356 endangered species of plants and

animals in the United States. These endangered organisms included

32 species of mammals,

61 species of birds,

8 species of reptiles,

5 species of amphibians,

45 species of fishes,

3 species of snails,

32 species of clams,

8 species of crustaceans,

10 species of insects,

3 species of spiders, and

140 species of plants.

Construct a bar graph of each of the numbers of endangered plant and animal species in 1989. Be sure to

reread about how to do a bar graph versus a histogram!

Title:

III. Using standard errors (S.E.) can help one visualize if there is a significant difference between two groups. If

the error bars overlap, there is likely no difference and if there is no overlap, then there is likely a difference.

Note that this does not work with standard deviation, only standard error. Study the graph below and answer

the accompanying questions assuming the bars represent one standard error.

Is there a significant difference in food

consumption (yes/no/too close to tell)

between containers having

A. 1 vs 3 slugs? __________

B. 3 vs 5 slugs? __________

C. 1 vs 5 slugs? __________

IV. Sometimes rates can be determined from graphs by determining the slope (ΔY/ΔX). Study the X,Y

graph on page one and determine the change in population per day (include units!)

A. between days 3 and 4. __________ B. between days 3 and 5. __________

V. Study the dual Y graph on page 2 and answer the following questions.

A. In which year is the moose population the greatest? __________

B. What is the moose population in that year? __________

C. In which year is the wolf population the greatest? __________

D. What is the wolf population in that year? __________

VI. The mean is the average so add up the values and divide by the number of values.

The mode is the value that is most common.

The median is the value in the middle when all values are ordered from lowest to highest. If an

even number of values exist, then the median is the average of the middle two values.

The range is the difference between the lowest and highest value of a set of values.

Study the flu outbreak data in Question I and solve for the following. Round to nearest whole

number.

A. mean __________ B. mode __________ C. median __________ D. range ______

VII. Identify two differences between a bar graph and a histogram.