pval_shapiro {DemographicTable}

R Documentation

P-value from modified Shapiro-Wilk Normality Test

Description

Obtain p-value from Shapiro-Wilk normality test, taking into consideration of several exceptions.

Usage

pval_shapiro(x, CLT = FALSE)

Arguments

x	double vector
CLT	logical scalar, whether to allow the use of Central Limit Theorem (default FALSE)

Details

pval_shapiro provides a pseudo p-value for the several exceptions of shapiro.test function, serving as a criteria of whether robust statistics/tests need to be used

• length(x) < 3L return 0, robust methods needed

• length(x) > 5e3L return 1, no robust method needed (robust methods could be too slow)

• CLT & length(x) > 30L return 1, no robust method needed because of the use of Central Limit Theorem

• all x values identical return 0, robust methods needed.

• Otherwise use the p-value from shapiro.test

Value

pval_shapiro returns a double scalar.

Examples

pval_shapiro(rnorm(5))
sapply(with(airquality, split(Ozone, f = Month)), FUN = pval_shapiro)

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