How to Perform a Normality Test on Minitab
Write the hypothesis., Choose the data., Paste the data in Minitab worksheet., Click “Stat”., Click "Basic Statistics". ,Click “Normality Test” , Select data., Click "Ok". , Understand the p-value displayed in the Normal Probability Plot., Infer the...
Step-by-Step Guide
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Step 1: Write the hypothesis.
A good way to perform any statistical analysis is to begin by writing the hypothesis.
For normality test, the null hypothesis is “Data follows a normal distribution” and alternate hypothesis is “Data does not follow a normal distribution”. -
Step 2: Choose the data.
Select and copy the data from spreadsheet on which you want to perform the normality test. , Open Minitab and paste the data in Minitab worksheet. , In the menu bar of Minitab, click on Stat. ,,, A small window named “Normality Test” will pop-up on the screen.
Click on the available option inside the white box and then Click “Select”.
Be aware that the “Variable” tab will have the name of selected data.
Also be aware that “Anderson-Darling” is already selected under “Tests for Normality”.
Anderson-Darling is the most widely used Normality test.
Hence, in Minitab, the default selection of Tests for Normality is “Anderson-Darling”. ,, A normal probability plot will appear on the screen.
Please observe if the p-value displayed in the normal probability plot is greater than
0.05 or is it lesser than
0.05. , As described in the step of writing the hypothesis, if we fail to reject the null hypothesis, the inference will be “Data follows a normal distribution”.
If we reject the null hypothesis, the inference will be “Data does not follow a normal distribution”.
Let’s link the p-value to the written hypothesis. , If the p-value observed in normal probability plot is greater than
0.05, we fail to reject the null hypothesis.
Thus the inference is “Data follows a normal distribution”. , If the p-value observed in normal probability plot is less than
0.05, we reject the null hypothesis.
Thus the inference is “Data does not follow a normal distribution”. -
Step 3: Paste the data in Minitab worksheet.
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Step 4: Click “Stat”.
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Step 5: Click "Basic Statistics".
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Step 6: Click “Normality Test”
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Step 7: Select data.
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Step 8: Click "Ok".
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Step 9: Understand the p-value displayed in the Normal Probability Plot.
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Step 10: Infer the results.
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Step 11: Do not reject null hypothesis if p-value is greater than 0.05.
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Step 12: Reject the null hypothesis if p-value is lesser than 0.05.
Detailed Guide
A good way to perform any statistical analysis is to begin by writing the hypothesis.
For normality test, the null hypothesis is “Data follows a normal distribution” and alternate hypothesis is “Data does not follow a normal distribution”.
Select and copy the data from spreadsheet on which you want to perform the normality test. , Open Minitab and paste the data in Minitab worksheet. , In the menu bar of Minitab, click on Stat. ,,, A small window named “Normality Test” will pop-up on the screen.
Click on the available option inside the white box and then Click “Select”.
Be aware that the “Variable” tab will have the name of selected data.
Also be aware that “Anderson-Darling” is already selected under “Tests for Normality”.
Anderson-Darling is the most widely used Normality test.
Hence, in Minitab, the default selection of Tests for Normality is “Anderson-Darling”. ,, A normal probability plot will appear on the screen.
Please observe if the p-value displayed in the normal probability plot is greater than
0.05 or is it lesser than
0.05. , As described in the step of writing the hypothesis, if we fail to reject the null hypothesis, the inference will be “Data follows a normal distribution”.
If we reject the null hypothesis, the inference will be “Data does not follow a normal distribution”.
Let’s link the p-value to the written hypothesis. , If the p-value observed in normal probability plot is greater than
0.05, we fail to reject the null hypothesis.
Thus the inference is “Data follows a normal distribution”. , If the p-value observed in normal probability plot is less than
0.05, we reject the null hypothesis.
Thus the inference is “Data does not follow a normal distribution”.
About the Author
Theresa Morales
Creates helpful guides on organization to inspire and educate readers.
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