pcares (Statistics Toolbox)

Residuals from a Principal Components Analysis

Syntax

```
residuals = pcares(X,ndim)
```

Description

pcares(X,ndim) returns the residuals obtained by retaining ndim principal components of X. Note that ndim is a scalar and must be less than the number of columns in X. Use the data matrix, not the covariance matrix, with this
function.

Example

This example shows the drop in the residuals from the first row of the Hald data as the number of component dimensions increase from one to three.

load hald
r1 = pcares(ingredients,1);
r2 = pcares(ingredients,2);
r3 = pcares(ingredients,3);
r11 = r1(1,:)
r11 =
    2.0350    2.8304   -6.8378    3.0879
r21 = r2(1,:)
r21 =
   -2.4037    2.6930   -1.6482    2.3425
r31 = r3(1,:)
r31 =
    0.2008    0.1957    0.2045    0.1921

Reference

[1] Jackson, J. E., A User's Guide to Principal Components, John Wiley and Sons, Inc. 1991. pp. 1-25.

See Also
barttest, pcacov, princomp

pcacov pdf