Conduct a Bartlett's test for sphericity on a set of variables.
Technical details
Description
This test is used to make sure that the correlation matrix of the variables in your dataset diverges significantly from the identity matrix. An identity matrix is a matrix in which all of the values along the diagonal are 1 and all of the other values are 0. If the p-value from Bartlett’s Test of Sphericity is lower than your chosen significance level (common choices are 0.10, 0.05, and 0.01), then we can assume that the variables in the correlation matrix are not orthogonal.
Inputs
You should use numeric variables as inputs. If you use categorical or ordinal variables, they will be coerced to numeric based on their values for the purposes of running the test.
- Input Variables The variables that you would like to analyze.
- Missing data See Missing Data Options.
- Variable names Display Variable Names in the output, instead of Variable Labels.
- More decimal places Display numeric values with 8 decimal places.
Output
An output is created below:
Additional Properties
When using this feature you can obtain additional information that is stored by inspecting it using custom R code in an item below:
#change YourReferenceName to the reference name (under Properties > General) of your analysis
item = YourReferenceName
str(item)
Acknowledgements
The function cortest.bartlett from the R package psych is used to conduct the Bartlett test.
Method
- In Displayr: How to Do a Barlett's Test of Sphericity
- In Q: Create > Test > Bartlett Test of Sphericity