Bartlett's Test Calculator
Bartlett's test is used to test the assumption that variances are equal (homogeneous) across groups.
For help in using this calculator, read the
Frequently-Asked Questions or review the
Sample Problem.
To learn more about Bartlett's test, read Stat Trek's
tutorial on Bartlett's test.
- Enter inputs in unshaded text boxes.
- Click the Calculate button to produce outputs.
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Frequently-Asked Questions
Instructions: To find the answer to a frequently-asked
question, simply click on the question.
Sample Problem
Problem 1
The table below shows sample data and variance for five groups. How would you test the assumption that variances are equal across groups?
Group 1 |
Group 2 |
Group 3 |
Group 4 |
Group 5 |
Sample Data |
1 2 3 4 5 |
1 3 5 7 9 |
1 4 7 10 13 |
1 5 9 13 17 |
1 6 11 16 21 |
Variance |
2.5 |
10 |
22.5 |
40 |
62.5 |
One option would be to use Stat Trek's Bartlett's Test Calculator. Simply, take the following steps:
- Enter the number of groups (5).
- Enter the significance level. For this problem, we'll use 0.05.
- For each group, enter sample size.
- For each group, enter a sample estimate of group variance.
Then, click the Calculate button to produce the output shown below:
From the calculator, we see that the test statistic (T) is 8.92. Assuming equal variances in groups and given a significance level of 0.05,
the probability of observing a test statistic (T) bigger than 8.92 is given by the P-value.
Since the P-value (0.06) is bigger than the significance level (0.05), we cannot reject the null hypothesis
of equal variances across groups.
Note: To see the hand calculations required to solve this problem, go to
Bartlett's Test for Homogeneity of Variance: Example 1.