count.combn {ThurMod}

Count paired comparisons

Description

This function calculates the number of paired comparisons needed to compare a set of N items.

Usage

count.combn(nitem)

Arguments

nitem

Number of items.

Details

This function is only useful, if the number of paired comparisons of a full design, that is all possible paired comparisons, is of interest. Then the number is

\frac{N\times(N-1)}{2}

Value

An integer corresponding to the number of paired comparisons.

Examples

# Number if paired comparisons for a set of 15 items = 105.
count.combn(15)