Graphs, Tables, and Charts
a how to guide
Making Data Tables and Graphs
An experiment shows the effect of
fertilizer on the mass of tomatoes, with
the observation that Fertilizer X
produces a higher mass in tomatoes
than other brands of fertilizer. How is
the data communicated and what does
it mean?
What do you include in tables and
graphs?
• Data entry into a table should be neat and
legible with 2 or more columns/rows
• Descriptive title (how the Independent
Variable affects the Dependent Variable)
• Independent Variable in the first column/row
with unit in parentheses
• Dependent Variable in the second
column/row with unit in parentheses
• Data collected in ordered pairs/coordinates
(two pieces of data that are directly related to
each other)
Making a Table
The Effect of Fertilizer on
the Mass of Tomatoes
Fertilizer
Mass of
Tomatoes (g)
W
X
Y
Z
210
275
235
200
Ordered Pairs
Title
Dependent Variable
(unit)
Independent Variable
(unit)
Making a Table
•Data on the previous slide showed only one
tomato plant’s growth
•REMEMBER: there should be at least 3 trials
for the experiment to be more accurate.
•The table can also show the average of each
experimental group and the control group.
•When typing, make sure the table is on one
page. If it continues to the next page, you
must label with the title and column/row
headings again.
Making a Table
•For Example:
Title to reflect relationship
between dependent and
independent variable
(Independent
Variable)
The Effect of Fertilizer on the (Dependent
Variable)
Mass of Tomatoes
Tomato 1 Tomato 2 Tomato 3 Average
Fertilizer
(g)
(g)
(g)
Mass (g)
Z
190
200
210
200
W
210
220
200
210
Y
230
235
240
235
X
280
285
260
275
Ordered
Pairs
Now we can graph
• Data is in a table, and can now be moved into
a graph.
• A graph will show trends and patterns in
the data.
What kind of graph do I need?
• Bar Graph – use when ordered pairs
are compared that are discrete, such as
brand of paper towel.
• number vs name
• The independent variable is all text or
numbers representing text (i.e. sample
1, sample 2)
• The independent variable is not a
measurement (i.e. green, blue, yellow)
What kind of graph do I need?
• Line Graph – use when different
measurements of the same item are recorded
over time (continuous)
• number vs number
• Time
• Temperature
What kind of graph do I need?
DRY
•In both bar and line graphs, the independent
variable and unit are located on the X axis; the
dependent variable and unit are located on the Y
vertical axis.
Remember this clue:
DRY (Dependent Responding Y axis)
MIX (Manipulated Independent X axis)
MIX
This graph shows 3 trials
Mass of Tomatoes (g)
The Effects of Fertilizer on Tomato Mass
300
Z
200
W
100
Y
X
0
Tomato
Trial 1 1
Tomato
Trial 2 2
Tomato
Trial 3 3
This graph shows the average of the
three trials
Mass of Tomato
(g)
Effect of Fertilizer on Tomato Mass
300
200
Average
100
0
Z
W
Y
Fertilizer
X
This graph shows the average of the
three trials
Mass of Tomato
(g)
Effect of Fertilizer on Tomato Mass
300
200
Average
100
0
Z
W
Y
Fertilizer
X
Line Graph Example:
The data in the next graph was collected on
plant growth over a seven month period.
The height of the plants was measured in
centimeters.
Line Graph Example:
Plant Growth Over Time
Independent
Variable
Time
(month)
1
2
3
4
5
6
7
Plant
Height
(cm)
0
23
48
63
98
120
150
Dependent
Variable
Line Graph Example:
Plant Growth Over Time
Plant Height (cm)
175
150
125
100
75
50
25
0
1
2
3
4
Time (months)
5
6
7
Line Graph Rules:
•
•
•
•
•
Refer to the Graphing Handout.
When in doubt, use a line graph.
Label each axis, give units.
All graphs have an origin of (0,0)
You may use a “squiggle” to indicate
a break in the number sequencing.
• Never graph across this.
Line Graph Rules:
• Extrapolated (hypothesized) points are
indicated differently from measured point.
• Extrapolated points are hollow
• Interpolated (measured) points are solid
• Extrapolation: Use dotted line on the
extension of your life beyond the measured
points on graph.
Line Graph Rules:
• If data has linear progression, use “best fit
line,” otherwise, “connect the dots.”
• Do NOT draw both!
What kind of graph do I need?
• Pie Chart – use when pieces of a whole are
shown
• % adds to 100
Percentage of Species of Whales
Independent
Variable
Determine
the total
number
Type of Number of
Whale
Whales
minke
30
whale
blue whale
100
gray whale
50
right whale
50
sperm
60
whale
killer whale
30
narwhal
15
Total
335
Percent of Dependent
Variable
population
8.96%
29.85%
14.93%
14.93%
17.91%
8.96%
4.48%
100.00%
Find
the %
of
each
piece
of data
Pie Chart
In this case the percentage of certain types of
whales is shown. Does a percentage have
to be
Percent Whales
determined
to make this
4%
9%
9%
minke whale
comparison
blue whale
with this
gray whale
18%
30%
right whale
data?
sperm whale
killer whale
narwhal
15%
15%
Pie Chart
This graph shows the whale data based on their
numbers and not percent of the population.
Whale Population Numbers
minke whale
30 15 30
blue whale
gray whale
60
100
right whale
sperm whale
50
50
killer whale
narwhal
What’s wrong with this graph?
What’s wrong with this graph?
What’s wrong with this graph?
Which is easier to read?
Let’s Review
A student experimented to find out how table salt affects the
freezing point of water. After cooling distilled water with ice,
the temperature was measured and recorded. Several more
measurements were taken in regular intervals after specific
amounts of table salt were added.
Which data table is best constructed to represent this data?
Title
Title
Water +
Salt (g)
Temp.
(oC)
Temp.
(oC)
Water+
Salt (g)
Water +
Salt
Temp.
(g)
(oC)
1
5
2
3.1
0
5
0
1
3.1
3.1
1
2
2.4
3
2.4
1.3
2.4
2
3
1.3
4
1.3
-.5
1.3
3
4
-.5
5
-.5
-.5
4
0
5
1
3.1
5
2
2.4
3
4
A
Title
Title
B
C
D
Let’s Review
Table A has all the correct components of independent variable on the left
column and dependent variable in the right. A title is given and the units
are provided in the column heading.
Table B shows independent and dependent variables at incorrect positions.
Table C does not include units in the column descriptions.
Table D does not describe the variables
A
B
Title
Water +
Salt (g)
C
Title
Temp.
(oC)
Temp.
(oC)
D
Title
Water+
Salt (g)
Water +
Salt
Title
Temp.
(g)
(oC)
0
5
1
5
5
1
3.1
2
3.1
101
3.1
2
2.4
3
2.4
1.3
102
2.4
3
1.3
4
1.3
-.5
103
1.3
4
-.5
5
-.5
104
-.5
0
5
1
3.1
100
2
2.4
3
4
Let’s Review
A student experimented to find out how table salt
affects the freezing point of water. After cooling .5 L
of distilled water with ice, the temperature was
measured and recorded. Several more
measurements were taken in regular intervals after
specific amounts of table salt in grams were added.
When graphing the results of this procedure,
which variable should the students place on
the Y axis?
A. freezing point of water
B. grams of salt added to the ice
C. the amount of ice added to the water
D. temperature of the water
Let’s Review
Answer D
A. freezing point of water The temperature of the
water only at freezing point shows only one data
point and neglects data read to that point.
B. grams of salt added to the ice This is the
independent variable which is located on the X
axis.
C. the amount of ice added to the water This would not
be a factor to be graphed.
D. temperature of the water This is the dependent
variable which is placed on the Y axis. The
temperature of the water changes in response to
the addition of salt.
Let’s Review
A beaker with 250 mL of water was left in a
window where sunlight entered. The
temperature of the water was measured with a
sensor every 2 minutes in a 45 minute period.
The rate at which the water temperature rose
was then determined. In what kind of graph
would the data best be displayed?
A. Bar graph
B. Line graph
C. Pie chart
D. Pictograph
Let’s Review
Answer B
The data is continuous for both dependent and
independent variables, making only a line graph
appropriate to illustrate this data. Both time and
temperature are measured continuously throughout the
data collection of the water temperature.
A. Bar graph a bar graph is used with data is discrete
and may be descriptive, such as type of paper
towel.
B. Line graph
C. Pie chart A pie chart is used when comparing
numbers or percentages of items.
D. Pictograph A pictograph is used with actual
images or pictures of items.
Let’s Review
This graph shows information
for a specific date, Dec. 15,
over a period of 8 years. Is
this data best illustrated in a
line graph?
A. Yes because both dependent and
independent variables contain discrete data.
B. Yes the data between points are continuous
and have meaning.
C. No because the data would be better shown
with a pie graph.
D. A bar graph would be better because it is
easily constructed with this data.
Dec. 15 Temperatures, Max & Min.
Temperature/Celsius
25
20
Loc. 2 Max
15
Loc. 2 Min
10
5
0
1994 1995 1996 1997 1998 2000 2001 2002
Year
Let’s Review
Answer B
A.Yes because both dependent and Independent
variables contain discrete data. The dependent
variable, temperature is continuous data.
B.Yes the data between points is continuous and has
meaning. This is the correct answer.
C.No because the data would be better shown with a
pie graph. This data does not show a percent or
number that can be illustrated in a pie graph.
D.A bar graph would be better because it is easily
constructed with this data. The ease of graph
construction should not be considered in the type
of graph that best illustrates the data.
Let’s Review
Lupe needed to know the composition of soil in
her flowerbed before deciding what to plant based
on the information. She sent the soil to an
agricultural extension service to get the results.
The report showed that the soil contained 5%
organic, 10% clay, 3% sand, 45% mineral, 20%
air, and 17% gravel. What type of graph best
illustrates this information?
A.Bar graph
B.Double line graph
C.Line graph
D.Pie chart
Let’s Review
Answer D
Dependent and independent variables are not
found in this type of information. Only a pie
chart would be appropriate. A pie chart
easily illustrates percentages in data.