Anderson Darling normality test

To check if the data set is distributed according the normal distribution.

Interpretation

• The smaller the p value the more unlikely the dataset is normally distributed.
• In Develve the minimum p value for normality is 0.10.
• The minimum advised sample size for this test is 20 samples.
• Alway check the Histogram of the dataset.
• What to do with not normally distributed Data

Colors of the cells

• Orange Sample size it to small
• Red Dataset is not normally distributed

Normal distributed data set

Not normal distributed data set

Formula

Correction factor for small sample sizes.

With the A² value can the program interpolate in a table the p value.

Legend

n = n

Example

Datasets C is not normally (normality p <0.10) distributed therefore statistical test that assume normality are colored red.

External links

• http://en.wikipedia.org/wiki/Anderson%E2%80%93Darling_test
• http://www.itl.nist.gov/div898/handbook/eda/section3/eda35e.htm
  

To check the normality of a data set.