The Shapiro-Wilk Normality Test checks whether a sample comes from a normally distributed population. It is applicable for 3 to 5000 data points. The node outputs two values: the test statistic W and the corresponding p-value. To accept or reject the null hypothesis, one can either compare W to a predefined threshold Wcritical or use a threshold for the p-value. Since the test is biased by sample size, the test may be statistically significant from a normal distribution in any large samples. Thus a Q–Q plot is required for verification in addition to the test. More information about this test can be found on Wikipedia .