# Scale

## Contents

### Purpose

Scales data using specified means and standard deviations.

### Synopsis

sx = scale(x,means,stds,options)
sx = scale(x,means)

### Description

sx = scale(x,means) subtracts a vector means from a matrix x and returns the result as sx. If means is the vector of means this routine mean centers x.

sx = scale(x,means,stds) subtracts a vector means from a matrix x, divides each column by the corresponding element in the vector stds and returns the result as sx. If means is the vector of means and stds is the vector of standard deviations this routine auto-scales x so that each column of sx has zero mean and unit variance.

The optional input (options) is defined below.

### Options

The optional input (options) is an options structure containing:

• stdthreshold:  scalar value or vector of standard deviation threshold values. If a standard deviation is below its corresponding threshold value, the threshold value will be used in lieu of the actual value. A scalar value is used as a threshold for all variables.
• samplemode:  mode of x which should be considered the "sample" mode. Default is 1, rows. This is the mode over which the scaling and subtracting are done.