Name: _______________________________________________
Hour: _____
Biology Graphing Practice
Introduction:
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Graphing is an important procedure used by scientists to display the data that is collected during a
controlled experiment
A graph contains 4 major parts:
a. Title
b. Independent variable
c. Dependent variable
d. Scales for each variable (…and a legend/key if needed)
The Title: depicts what the graph is about. By reading the title, the reader should get an idea about
the graph. It should be a concise statement placed above the graph.
The Independent Variable: is the variable that can be controlled by the experimenter. (I KNOW
THIS MEASUREMENT AT THE BEGINNING OF THE EXPERIMENT!) It usually includes
time (dates, minutes, hours), depth (feet, meters), temperature (Celsius). This variable is placed on
the X axis (horizontal axis).
The Dependent Variable: is the variable that is directly affected by the independent variable. It is
the result of what happens because of the independent variable. (YOU DO NOT KNOW THIS
MEASUEMENT AT THE BEGINNING OF THE EXPERIMENT!) Example: How many oxygen
bubbles are produced by a plant located five meters below the surface of the water? The oxygen
bubbles are dependent on the depth of the water (independent). This variable is placed on the Yaxis or vertical axis.
The Scales for each Variable: In constructing a graph one needs to know where to plot the points
representing the data. In order to do this a scale must be employed to include all the data points.
This must also take up a conservative amount of space. The scales should start with 0 and climb
based on intervals such as: multiples of 2, 5, 10, 20, 25, 50, or 100. The scale of numbers will be
dictated by your data values.
The mean for a group of variables: To determine the mean for a group of variables, divide the sum
of the variables by the total number of variables to get an average.
The median for a group of variables: To determine median or “middle” for an even number of
values, put the values in ascending order and take the average of the two middle values. e.g. 2, 3,
4, 5, 9, 10 Add 4+5 (2 middle values) and divide by 2 to get 4.5
The mode for a group of variables: The mode for a group of values is the number that occurs most
frequently. e.g. 2, 5, 8, 2, 6, 11 The number 2 is the mode because it occurred most often
(twice).
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Problem #1:
Using the following data, answer the questions below and then construct a line graph.
Depth in water in meters Number of Bubbles / minute Plant A Number of Bubbles / minute Plant B
2
29
21
5
36
27
10
45
40
16
32
50
25
20
34
30
10
20
1. What is the dependent variable?
2. What is the independent variable?
3. What title would you give the graph?
4. What are the mean, median, and modes for the following data?
a). Depth :
Mean____________ Median_________ Mode________
b). Bubbles Plant A.:
Mean ____________ Median_________ Mode________
c). Bubbles Plant B:
Mean ____________ Median_________ Mode________
5. Construct a line graph
Problem #2:
Diabetes is a disease affecting the insulin producing glands of the pancreas. If there is not enough
insulin being produced by these cells, the amount of glucose in the blood will remain high. A blood
glucose level above 140 for an extended period of time is not considered normal. This disease, if not
brought under control, can lead to sever complications. Answer the following questions concerning
the data below and then graph it.
mL of Glucose / L of Blood mL of Glucose / L of Blood
Time After Eating (hours)
Person A
Person B
0.5
170
180
1
155
195
1.5
140
230
2
135
245
2.5
140
235
3
135
225
4
130
200
2
1. What is the dependent variable?
2. What is the independent variable?
3. What title would you give the graph?
4. Which, if any, of the above individuals (A and/or B) has diabetes?
5. What data do you have to support your hypothesis?
6. Construct a line graph
Problem #3: Rabbits Over Time
a. The graph shows a
_______________ growth curve.
b. The carrying capacity for
rabbits is ____ rabbits.
c. During which month were the
rabbits in exponential growth?
***Hint: See pg. 93-94
Problem #4: Average Toe Length
a. In 1800, about how many
people surveyed had a 3 cm
toe? __________
How many in 2000?
__________
b. The data shows the
________________
selection has occurred?
c. In 2000, what is the
average toe length?
________ What is the
average toe length in 1800
_________?
***Hint: See pg. 408
3
Problem #5: Mexico and US
a. In Mexico, what percentage
of the population is between 0-4
years of age? _________ In the
US? _________
b. Which population is growing
the fastest? ____________
c. Which age group has the
smallest number in both
countries? _________
***Hint: See pg. 103
Problem # 6:
Amount of ethylene in
ml/m2
Wine sap
Apples:
Days to
Maturity
Golden Apples:
Days to
Maturity
Gala Apples:
Days to
Maturity
10
14
14
15
15
12
12
13
20
11
9
10
25
10
7
9
30
8
7
8
35
8
7
7
Ethylene is a plant hormone that causes fruit to mature. The data above concerns the amount of
time it takes for fruit to mature from the time of the first application of ethylene by spraying a
field of trees.
1. Construct a line graph
2. What is the dependent variable?
3. What is the independent variable?
4
Problem # 7:
Age of the
tree in years
Average thickness of the
annual rings in cm.
Forest A
Average thickness of the
annual rings in cm.
Forest B
10
2.0
2.2
20
2.2
2.5
30
3.5
3.6
35
3.0
3.8
50
4.5
4.0
60
4.3
4.5
The thicknesses of the annual rings indicate what type of environmental situation was occurring
at the time of its development. A thin ring usually indicates a rough period of development:
Lack of water, forest fires, or a major insect infestation. On the other hand, a thick ring
indicates just the opposite.
1. Construct a line graph of the data.
2. What is the dependent variable?
3. What is the independent variable?
4. What was the average thickness of the annual rings of 40 year old trees in Forest A?
5. Based on this data, what can you conclude about Forest A and Forest B?
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Problem # 1
Title: _______________________________________________________________________
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Problem #2
Title: _____________________________________________________________________________
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Problem #6
Title: _____________________________________________________________________________
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Problem #7
Title: _____________________________________________________________________________
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