Scatter Diagram
- 1. © Sun Technologies Inc. 1 Scatter Diagram
- 2. © Sun Technologies Inc. 2 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.
- 3. © Sun Technologies Inc. 3 • 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.
- 4. © Sun Technologies Inc. 4 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.
- 5. © Sun Technologies Inc. 5 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.
- 6. © Sun Technologies Inc. 6 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.
- 7. © Sun Technologies Inc. 7 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
- 8. © Sun Technologies Inc. 8 T JTE STE TL M 20 40 60 80 100 Employees NoofTestCases
- 9. © Sun Technologies Inc. 9 Thank you