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Bartlett's test

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QXL Stat Tools Tab > Hypothesis Tests > Tests for Variance > Bartlett's test

Test type: Variance
Data: Quantitative
Number of Variables: 1
Number of Groups: 2 or more
Assumptions: Normally distributed samples

Bartlett's test is a hypothesis test used for testing variance equality between samples of two or more populations. It assumes that samples come from independent populations and that they are normally distributed. If samples are not normally distributed, use Levene's test.

Hypothesis tested:

H0 : σ1 = σ2 = ... = σn
H1 : σi ≠ σj

where σk is the population variance.

Step #1: Select data source for Bartlett's test.

Data for the Bartlett's test can come from an Excel spreadsheet, SQL data source, or it can be entered manually.

See source data formats and example data for the Bartlett's test.

Step #2: Options.

  • 'Decision Criteria' option (default = 0.05). The value of the decision criteria (significance or α level).

  • 'Box Plot'option. Display box plot hypothesis results.

  • 'Display mode' option. When the 'Verbose (long)' option is on, Quantum XL will display additional text that explains the hypothesis test results.

Example

Bartlett's test results

Quantum XL will display test statistic (F), p Value, 95% Bonferroni CI for StDevs, and dataset statistics.

In this example, the p-Value is very small (2*10-9). Since it is less than the decision criteria (0.05), the null hypothesis can be rejected. We can draw the conclusion that the variances are different.

Update

Bartlett's test is updatable. After you create analysis, you can change its data source or add new data to the data source and simply update the analysis.

  • Update: Quantum XL > Statistical Tools > Update Sheet

  • Change settings: Quantum XL > Statistical Tools > Modify Chart/Analysis