Scatter Diagram

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Scatter Diagram

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What is Scatter Diagram?
The scatter diagram graphs pairs of numerical data, with
one variable on each axis, to look for a relationship
between them. If the variables are correlated, the points
will fall along a line or curve.

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• The scatter diagram is used to find the
correlation between two variables.
• This diagram shows you how closely the
two variables are related.
• After determining the correlation between
the variables, you can easily predict the
behavior of the other variable.
• This chart is very useful when one
variable is easy to measure and the other
is not.

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When to Use a Scatter Diagram?
When you have paired numerical data.
When your dependent variable may have multiple values for
each value of your independent variable.
When trying to determine whether the two variables are related,
such as,
• When trying to identify potential root causes of problems.
• When testing for autocorrelation before constructing a control chart.

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Limitations of a Scatter Diagram
The following are a few limitations of a scatter diagram:
• Scatter diagram is unable to give you the exact extent of
correlation.
• Scatter diagram does not show you the quantitative measure of
the relationship between the variable. It only shows the
quantitative expression of the quantitative change.
• This chart does not show you the relationship for more than two
variables.

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Benefits of a Scatter Diagram
The following are a few advantages of a scatter diagram:
• It shows the relationship between two variables.
• It is the best method to show you a non-linear pattern.
• The range of data flow, i.e. maximum and minimum value, can be
easily determined.
• Observation and reading is straightforward.
• Plotting the diagram is relatively simple.

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Example
By using two variables, Test Cases and Employees with designation in scatter diagram, it is
easy to determine the best productivity of employees.
Test Cases Employees
90 Manager
60 Test lead
35 Senior Test Engineer
40 Junior Test Engineer
20 Trainee

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T JTE STE TL M
20
40
60
80
100
Employees
NoofTestCases

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Thank you