canprot (version 1.0.0)

rankdiff: Weighted Difference of Sums of Ranks

Description

Calculate rank-sum difference between two groups, weighted by the sizes of the groups.

Usage

rankdiff(rank1, rank2, n1 = NULL, n2 = NULL, as.fraction=TRUE)

Arguments

rank1

numeric, ranks in group 1

rank2

numeric, ranks in group 2

n1

numeric, size of group 1

n2

numeric, size of group 2

as.fraction

logical, calculate the fraction of maximum possible difference?

Details

In a combined ranking of two groups, the comparison of sum of ranks has an easy interpretation only for groups of equal size. The weighted rank difference is used to compare groups of unequal size. The weighting ensures that 1) opposite extreme configurations give weighted rank differences with equal magnitudes, and 2) an evenly distributed (interspersed) ranking of the two groups has a weighted rank difference of zero (Dick, 2016).

If n1 and n2 are not given, rank1 and rank2 are interpreted as vectors holding the ranks for the two groups. If the sizes of the groups are supplied in n1 and n2, then the single values or higher-dimensional objects in rank1 and rank2 are interpreted as the non-weighted sums of ranks of the two groups.

References

Dick, J. M. (2016) Proteomic indicators of oxidation and hydration state in colorectal cancer. PeerJ 4, e2238. 10.7717/peerj.2238

See Also

This function is used in groupplots.

Examples

# NOT RUN {
# rankings of H and C in H-H-H-H-C-C-C
rankdiff(1:4, 5:7, as.fraction=FALSE)  # 12
rankdiff(1:4, 5:7)  # 1

# rankings of H and C in C-C-C-H-H-H-H
rankdiff(4:7, 1:3, as.fraction=FALSE)  # -12
rankdiff(4:7, 1:3)  # -1

# rankings of H and C in H-C-H-C-H-C-H
rankdiff(c(1, 3, 5, 7), c(2, 4, 6))  # 0
# }