# tiedrank

## Syntax

```[R,TIEADJ] = tiedrank(X) [R,TIEADJ] = tiedrank(X,1) [R,TIEADJ] = tiedrank(X,0,1) ```

## Description

`[R,TIEADJ] = tiedrank(X)` computes the ranks of the values in the vector `X`. If any `X` values are tied, `tiedrank` computes their average rank. The return value `TIEADJ` is an adjustment for ties required by the nonparametric tests `signrank` and `ranksum`, and for the computation of Spearman's rank correlation.

`[R,TIEADJ] = tiedrank(X,1)` computes the ranks of the values in the vector `X`. `TIEADJ` is a vector of three adjustments for ties required in the computation of Kendall's tau. `tiedrank(X,0)` is the same as `tiedrank(X)`.

`[R,TIEADJ] = tiedrank(X,0,1)` computes the ranks from each end, so that the smallest and largest values get rank 1, the next smallest and largest get rank 2, etc. These ranks are used in the Ansari-Bradley test.

## Examples

Counting from smallest to largest, the two 20 values are 2nd and 3rd, so they both get rank 2.5 (average of 2 and 3):

```tiedrank([10 20 30 40 20]) ans = 1.0000 2.5000 4.0000 5.0000 2.5000 ```

## Algorithms

`tiedrank` treats `NaN`s in `X` as missing values and ignores them. The rank of `NaN`s in the output argument `R` is `NaN`.

## Version History

Introduced before R2006a