methodRuleWMW function

Function to pick the method for wmwTest given the data and exact argument.

Inputs x,y,exact, and chooseLimit, and outputs the method, one of 'asymptotic', 'exact.ce', or 'exact.mc'

methodRuleWMW(x, y, exact, chooseLimit = 5000)

Arguments

• x: vector of numeric responses from group 1
• y: vector of numeric responses from group 2
• exact: logical, should exact methods be used?
• chooseLimit: boundary for choosing between methods

Details

Let J=choose(m+n,n) where length(x)=m and length(y)=n. If exact=NULL then return 'exact.ce' if J is less than or equal to chooseLimit, otherwise return 'asymptotic'. If exact=FALSE return 'asymptotic'. If exact=TRUE then return 'exact.ce' if J is less than or equal to chooseLimit, otherwise return 'exact.mc'.

Returns

a character vector with one element, either: - asymptotic: for using normal approximations

• exact.ce: for using exact methods with complete enumeration

• exact.mc: for a Monte Carlo implementation of the exact version of the test

Examples

methodRuleWMW(rnorm(7),rnorm(7),exact=NULL)
methodRuleWMW(rnorm(7),rnorm(8),exact=NULL)