ztrans

### Table of Contents

# ztrans

## Motivation

Under certain circumstances (e.g. data that is arbitrarily scaled and comes from several sources has to be compared), one way to normalize (re-scale) the data is to apply z-transformation (setting the mean of values in the desired dimension to 0 and the standard deviation to 1).

## Function reference ('help ztrans')

ztrans - perform z-transformation on time course FORMAT: [ztc, zf, zsh] = ztrans(tc [, dim [, tp]]) Input fields: tc time course data dim temporal dimension (default: first non-singleton) tp time points (indices of dim to use for normalization) Output fields: ztc z-transformed time course zf z-transformation factor zsh z-transformation shift See also psctrans

## Usage examples

- z-transforming a single time-course (e.g. of a region or voxel):
ztc = ztrans(tc);

- z-transformation of an entire VTC (ensuring that dimension is 1):
vtc.VTCData = ztrans(vtc.VTCData, 1);

- z-transformation of 4D-NII VoxelData (ensuring that dimension is 4):
nii.VoxelData = ztrans(nii.VoxelData, 4);

- also obtaining the information about the scaling factor and shift:
[ztc, zfactor, zshift] = ztrans(tc);

ztrans.txt · Last modified: 2010/06/11 00:04 by jochen