ntester {PASWR}

Normality Tester

Description

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

Usage

ntester(actual.data)

Arguments

actual.data

is 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 plotted 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 based on the Shapiro-Wilk W-statistic. Function will only work on numeric vectors containing less than or equal to 5000 observations. Best used for moderate sized samples (n < 50).

Author(s)

Alan T. Arnholt <[e-mail]>

References

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

Examples

ntester(actual.data = rexp(40, 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 40.