The function CalcAndTestSkewness calculates the third moment and the skewness. Additionally it performs a test for the significance of the skewness. The array Data contains the data, the parameter OneSided controls whether the test is conducted onesided or twosided. The variable parameters m3 and Gamma return the third moment and the skewness, respectively. The variable zStatistic returns the value of the normally distributed statistic for the test.
The function value is the probability of the test. The null hypothesis has to be rejected if the probability is less than the level of significance. Depending on the parameter OneSided the following null hypotheses are assumed:
OneSided 
Null Hypothesis 
TRUE 
H_{0}: the distribution is skewed to the left 
FALSE 
H_{0}: the distribution is symmetric 
Returned error codes:
≥0 ... everything is OK, the returned value represents the pvalue
1 ... the number of data points is less than 8
2 ... standard deviation must not be zero
