Fundamental Features of Graphs
• All graphs have two, clearly-labeled axes that are drawn at
a right angle.
– The horizontal axis is the abscissa, or X-axis.
– The vertical axis is the ordinate, or Y-axis.
• The independent variable is plotted on the X-axis, and the
dependent variable is plotted on the Y-axis.
• The Y-axis must be a numerical scale.
• The length of the X- and Y- axis conforms to the ¾ rule.
• A graph contains only information related to the data and
information that is necessary to interpret the graph.
Choosing Graphs
• Graphs are selected based on the scale and continuity of
measurement.
Scale of
Measurement
Interval/Ratio
Continuity of
Measurement
Type of Graph
Continuous
Line Graph
Discontinuous
Histogram
Ordinal
Bar Chart
Nominal
Bar Chart
The Bar Graph
Mean Score
• The Bar Graph: a form of graph
that uses rectangles, or bars, to
represent nominal categories.
The bars do not touch.
• The nominal categories are
plotted on the X-axis.
• The Y-axis of the bar chart may
represent frequencies,
percentages, or descriptive
statistics such as the mean.
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68
66
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65
BOYSCORE
62
GIRLSCOR
High School
Some College
Professional Degree
Parent Education
Histograms
• Histogram: a form of
bar graph used to
represent information
when the X-scale is
interval or better.
The Line Graph
• Line Graph: a form of
graph in which a
continuous line
indicates the frequency
or statistic presented
along the Y-axis
Creating Graphs in SPSS
• In SPSS, you are given an option to create a graph any time
you perform a statistical operation
• Click analyze in the menu bar.
• Scroll down to descriptive statistics and select frequencies
from the pop out menu.
• In the frequencies dialog box, move the variable of interest to
the variable window by highlighting it and clicking on the
arrow.
• At the bottom of the window, click charts.
• In the charts dialog box, select the most appropriate graph for
the data type.
• Click continue. In the frequencies dialog box, click OK.
• You can double click on the graph to edit titles, intervals, etc.
Reading SPSS Graphs
Creating Graphs in SPSS
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To create graphs in SPSS, you can go to graphs in the menu bar.
Click graphs in the menu bar. Go to Legacy Dialogs.
Scroll down to the most appropriate graph.
In the chart dialog box, choose simple; summaries for groups of
cases. Click Define.
If you want to display the frequency of the variable, under bar/line
represents, do nothing.
If you want to display values of one variable as a function of another
variable, check “other statistic”; the box underneath should light up.
Select the dependent variable and move it to the variable box.
Select the independent variable and move it to the category axis box.
Click continue. Click OK.
Reading SPSS Graphs
Reading SPSS Graphs
Creating Graphs in Excel
• In all Excel graphs, Column A should include data for the Xaxis.
• In all Excel graphs, Column B should include data for the Yaxis.
• Highlight the data (scroll the mouse over cells) you wish to
use to create the chart.
• In the menu bar, click on insert and select the appropriate
chart (if you want a bar chart, select column).
• After the graph is generated, click on it to make the chart
tools available.
Creating Graphs in Excel
• Under chart tools, select layout.
– Remove chart title. Click on chart title and select none.
– Add axis titles. Click axis titles. Enter the titles for both the
horizontal (X) and vertical (Y) axes.
– Remove the horizontal gridlines. Click gridlines, horizontal
gridlines, none.
– Remove legend. Click legends and select none.
– For bar charts, insert data labels. Select data labels. Choose
inside end.
• Under chart tools, select format to change individual chart
elements (e.g. bar color) or select design to choose from
several preformatted styles and layouts.
• In the Excel spreadsheet, adjust the height and width of the
graph to follow the ¾ rule.
Reading Excel Graphs
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50
Frequnecy
48
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10
11
0
Grades
College
Peer Pressure Romantic
Parent
Adjustment
Relationships Relationships
Sources of Anxiety
Reading Excel Graphs
90
80
Memory Score
70
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20
10
0
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