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

TitleTitle

Fertilizer Mass of Tomatoes (g)

W 210

X 275

Y 235

Z 200

Dependent Variable (unit)

Dependent Variable (unit)

Independent Variable (unit)

Ordered Pairs

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 onepage. If it continues to the next page, you must label with the title and column/row headings again.

Making a Table

•For Example:(Dependent

Variable)

Ordered Pairs

The Effect of Fertilizer on the Mass of Tomatoes

Title to reflect relationship between dependent and

independent variable

(In

dep

end

ent

Va

riab

le)

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?

•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.

MIXD

RY

Remember this clue:DRY (Dependent Responding Y axis) MIX (Manipulated Independent X axis)

This graph shows 3 trials

Trial 2Trial 1 Trial 3

This graph shows the average of the three trials

This graph shows the average of the three trials

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

Dependent Variable

Line Graph Example:

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 areindicated differently from measured point.• Extrapolated points are hollow• Interpolated (measured) points are solid

• Extrapolation: Use dotted line on theextension of your life beyond the measuredpoints on graph.

Line Graph Rules:

• If data has linear progression, use “best fitline,” 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

Determine the total number

Find the % of each piece of data

Independent Variable

Dependent Variable

Percentage of Species of Whales

Pie Chart

In this case the percentage of certain types ofwhales is shown. Does a percentage have to be determined to make this comparison with this data?

Pie Chart

This graph shows the whale data based on their numbers and not percent of the population.

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 ReviewA 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

Water + Salt (g)

Temp. (oC)

0 5

1 3.1

2 2.4

3 1.3

4 -.5

Title

Water + Salt

Temp.

0 5

1 3.1

2 2.4

3 1.3

4 -.5

Title

(g) (oC)

1 5

2 3.1

3 2.4

4 1.3

5 -.5

A B C D

Title

Temp. (oC)

Water+Salt (g)

5 0

3.1 1

2.4 2

1.3 3

-.5 4

Let’s Review

Title

Water + Salt (g)

Temp. (oC)

0 5

1 3.1

2 2.4

3 1.3

4 -.5

Title

Water + Salt

Temp.

0 5

1 3.1

2 2.4

3 1.3

4 -.5

Title

(g) (oC)

1 5

2 3.1

3 2.4

4 1.3

5 -.5

A B C D

Title

Temp. (oC)

Water+Salt (g)

100 5

101 3.1

102 2.4

103 1.3

104 -.5

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

Let’s ReviewA 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 iceC. the amount of ice added to the waterD. 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 ReviewA 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 graphB. Line graphC. Pie chartD. Pictograph

Let’s ReviewAnswer B

A. Bar graph a bar graph is used with data is discrete and may be descriptive, such as type of paper towel.

B. Line graphC. 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.

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.

Let’s ReviewThis 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.

Let’s ReviewA.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.

Answer B

Let’s ReviewLupe 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 graphB.Double line graphC.Line graphD.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.