Graphs with SPSS

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Graphs with SPSS

• Aravinda Guntupalli

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Bar charts

• Bar Charts are used for graphical representation
  of Nominal and Ordinal data
• Height of the bar is proportional to the number
  of values in the category.
• Select the icon for the chart type you want, and
  select the option under Data.
• You can either show group of cases or groups of
  variables using bar chart.

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Summaries for Groups of Cases

• Categories of a single variable are summarized.
• Bar height is determined by the Bars Represent
  option.
• Example To see number of males and females from
  the Gender variable

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Bar chart for SES
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How to?

• From the menus, choose Graphs, Bar
• Select the icon for Simple and select Summaries
  for groups of cases.
• Select Define.
• Select a variable for the category axis and move
  it into the Category Axis box. This variable may
  be numeric, string, or long string.

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Summaries of groups of variables

• Two or more variables are summarized within
  categories of another variable.
• Two or more Bars Represent variables (Var 1, Var
  2).
• For example bar chart for gender and SES
  variables.

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Clustered Bar chart (a)
For Numeric variable
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How to?

• From the menus, choose Graphs and Bar
• Select the icon for Clustered and select
  Summaries of separate variables.
• Select Define.
• Select at least two variables and move them into
  the Bars Represent box. These variables must be
  numeric.
• Select a category variable and move it into the
  Category Axis box. This variable may be numeric,
  string or long string.

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Clustered Bar chart (b)
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How to?

• From the menus, choose Graphs and Bar
• Select the icon for Clustered and select
  Summaries of groups of cases.
• Select Define.
• Select at least two variables and move them into
  the Bars Represent box.
• These variables can be categorical.

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Pie Diagram

• The Pie Chart is an alternative to the Bar Chart
  for Nominal and Ordinal data.
• The proportion of the Pie represents the
  categorys percentage in the population or
  sample.
• Must identify slices.

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Pie diagram
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How to make pie diagram?

• From the menus, choose Graphs and Pie
• Select Summaries for groups of cases.
• Select Define.
• Select a variable and move it into the Define
  Slices by box. This variable may be numeric,
  string, or long string.

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Boxplot

• A boxplot consists of box and 2 tails.
• The horizontal line inside the box tells the
  position of the median and its upper and lower
  boundaries are its upper and lower quartiles.
• The tails run to the most extreme values.
• boxplot in sum shows structure of the data along
  with its skewness and spread.

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Boxplot
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How to make a boxplot?

• From the menus, choose Graphs and Boxplot
• Select the icon for Simple and select Summaries
  for groups of cases.
• Select Define.
• Select the variable for which you want boxplots,
  and move it into the Variable box.
• Select a variable for the category axis and move
  it into the Category Axis box. This variable may
  be numeric, string, or long string.

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Histogram

• A Histogram is a graphical representation of a
  frequency distribution for continuous data.
• The height is proportional to the frequency of
  that class

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Histogram (2)
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How to make histogram?

• From the menus, choose Graphs and Histogram
• Select a numeric variable for Variable in the
  Histogram dialog.
• Select Display normal curve to display a normal
  curve on the histogram.

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Skewness
Negatively skewed
Positively skewed
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• Number of modal classes
• A modal class is the one with the largest number
  of observations.

The modal class
A unimodal histogram
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Number of modal classes
A modal class
A modal class
A bimodal histogram
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Bell shaped histogram
Many Statistical techniques require normal
distribution. Histogram helps verify the shape
of population.
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Scatter plot (1)

• To know the relationships between two
  quantitative variables we are interested in we
  can use scatter plots.
• A scatter diagram plots the value of one economic
  variable against the value of another variable.
• It can be used to reveal whether a relationship
  exists and the type of relationship that exists.
• A scatter plot can describe the relation between
  reading and writing scores.

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Scatter plot (2)
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Typical Patterns
Negative linear relationship
Positive linear relationship
No relationship
Negative nonlinear relationship
Nonlinear (concave) relationship
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How to make scatter plots?

• From the menus, choose Graphs and Scatter
• Select the icon for Simple.
• Select Define.
• You must select a variable for the Y-axis and a
  variable for the X-axis. These variables must be
  numeric, but should not be in date format.
• You can select a variable and move it into the
  Set Markers by box. This variable may be numeric
  or string.

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P-P plots

• Plots a variables cumulative proportions against
  the cumulative proportions of any of a number of
  test distributions.
• Probability plots are generally used to determine
  whether the distribution of a variable matches a
  given distribution.
• If the selected variable matches the test
  distribution, the points cluster around a
  straight line.

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Normal P-P plot
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How to make P-P plots?

• From the menus, choose Graphs and P-P
• Select one or more numeric variables and move
  them onto the Variables list.
• Select a test distribution.

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Q_Q plots

• Plots the quantiles of a variable's distribution
  against the quantiles of any of a number of test
  distributions.
• Probability plots are generally used to determine
  whether the distribution of a variable matches a
  given distribution.
• If the selected variable matches the test
  distribution, the points cluster around a
  straight line.

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How to make Q-Q plots?

• From the menus, choose Graphs and Q_Q
• Select one or more numeric variables and move
  them onto the Variables list.
• Select a test distribution.

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Normal Q_Q plot
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Thank You

• Wish you colorful time making graphs