NSM3 (version 1.11)

pKW: Kruskal-Wallis

Description

Function to compute the P-value for the observed Kruskal-Wallis H statistic.

Usage

pKW(x,g=NA, method=NA, n.mc=10000)

Arguments

x

Either a list or a vector containing the data.

g

If x is a vector, g is a required vector of group labels. Otherwise, not used.

method

Either "Exact", "Monte Carlo", or "Asymptotic", indicating the desired distribution. When method=NA and ties are not present, "Exact" will be used. When method=NA and ties are present, "Exact" will be used if the number of permutations is 10,000 or less. Otherwise, "Monte Carlo" will be used.

n.mc

If method="Monte Carlo", the number of Monte Carlo samples used to estimate the distribution. Otherwise, not used.

Value

Returns a list with "NSM3Ch6p" class containing the following components:

n

a vector containing the number of observations in each of the data groups

obs.stat

the observed H statistic

p.val

upper tail P-value

Details

The data entry is intended to be flexible, so that the groups of data can be entered in either of two ways. For data a=1,2 and b=3,4,5 the following are equivalent:

pKW(x=list(c(1,2),c(3,4,5))) pKW(x=c(1,2,3,4,5),g=c(1,1,2,2,2))

See Also

Also see kruskal.test().

Examples

# NOT RUN {
##Hollander-Wolfe-Chicken Example 6.1 Half-Time of Mucociliary Clearance
mucociliary<-list(Normal = c(2.9, 3, 2.5, 2.6, 3.2), Obstructive = c(3.8, 
2.7, 4, 2.4), Asbestosis = c(2.8, 3.4, 3.7, 2.2, 2))

pKW(mucociliary)

# }