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Monte Carlo Analysis<br />

Additional Uncertainty Analyses (the .mcm File)<br />

==> Scale and Shape:<br />

Mu ... Maximum Likelihood (ML) Estimation to the Mean<br />

Sigma ... ML Estimation to the Standard Deviation<br />

Skewness ... Third Central Moment Divided by the Cube of Sigma<br />

Kurtosis ... Fourth Central Moment Divided by Fourth Power of Sigma<br />

(Sample Skewness and Kurtosis are Corrected for Bias)<br />

Index<br />

Name<br />

of Meas Mu Sigma Skewness Kurtosis of Meas<br />

----------------------------------------------------------------------------<br />

1 8.38289e-01 9.93480e-03 -5.07100e-02 2.90190e+00 MAX<br />

2 2.19635e+00 5.09067e-03 -3.76104e-02 2.90041e+00 BW<br />

3 -5.44169e-02 1.96232e-04 -3.38857e-02 3.17208e+00 IVDD<br />

D’Agostino-Pearson Test of Normality<br />

We provide the test of normality of D’Agostino-Pearson K 2 (K-squared test) based on the<br />

skewness and kurtosis coefficients. When these two numbers are different from the reference<br />

value, one may conclude that the empirical distribution is not compatible with the normal law.<br />

As the number of samples increase this test becomes particularly efficient when n ≥ 20, and is<br />

better than the Kolmogorov-Smirnov test. The idea is relatively simple. One tries to center and<br />

reduce the skewness and kurtosis indicators to obtain two statistics z 1 and z 2 . And one can prove<br />

that the statistics z 1 and z 2 are asymptotically normal. The D’Agostino-Pearson statistic is the<br />

combination:<br />

If the null hypothesis of normality is true, then K 2 is approximately distributed as the χ 2<br />

distribution with two degrees of freedom. Given a significance level α, the hypothesis regarding<br />

the normality is rejected if the test statistic satisfies:<br />

Tip<br />

For an instructive introduction to this test see: R. B. D’Agostino, A. Belanger and R. B.<br />

D’Agostino Jr, A suggestion for Using Powerful and Informative tests of Normality. The<br />

American Statistician, Vol 44, No 4. (1990), pp. 316-321.<br />

The results of this test are organized as classical hypothesis tests, see Hypothesis Tests section<br />

for more information.<br />

498<br />

Eldo® User's Manual, 15.3

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