ntester function

Normality Tester

Q-Q plots of randomly generated normal data of the same size as the tested data are generated and ploted on the perimeter of the graph while a Q-Q plot of the actual data is depicted in the center of the graph.

ntester(actual.data)

Arguments

• actual.data: a numeric vector. Missing and infinite values are allowed, but are ignored in the calculation. The length of actual.data must be less than 5000 after dropping nonfinite values.

Details

Q-Q plots of randomly generated normal data of the same size as the tested data are generated and ploted on the perimeter of the graph sheet while a Q-Q plot of the actual data is depicted in the center of the graph. The p-values are calculated form the Shapiro-Wilk W-statistic. Function will only work on numeric vectors containing less than or equal to 5000 observations.

Examples

ntester(rexp(50,1))
    # Q-Q plot of random exponential data in center plot
    # surrounded by 8 Q-Q plots of randomly generated 
    # standard normal data of size 50.

References

Shapiro, S.S. and Wilk, M.B. (1965). An analysis of variance test for normality (complete samples). Biometrika 52 : 591-611.

Author(s)

Alan T. Arnholt