summary.rlm {MASS} | R Documentation |

## Summary Method for Robust Linear Models

### Description

`summary`

method for objects of class `"rlm"`

### Usage

```
## S3 method for class 'rlm'
summary(object, method = c("XtX", "XtWX"), correlation = FALSE, ...)
```

### Arguments

`object` |
the fitted model.
This is assumed to be the result of some fit that produces
an object inheriting from the class |

`method` |
Should the weighted (by the IWLS weights) or unweighted cross-products matrix be used? |

`correlation` |
logical. Should correlations be computed (and printed)? |

`...` |
arguments passed to or from other methods. |

### Details

This function is a method for the generic function
`summary()`

for class `"rlm"`

.
It can be invoked by calling `summary(x)`

for an
object `x`

of the appropriate class, or directly by
calling `summary.rlm(x)`

regardless of the
class of the object.

### Value

If printing takes place, only a null value is returned.
Otherwise, a list is returned with the following components.
Printing always takes place if this function is invoked automatically
as a method for the `summary`

function.

`correlation` |
The computed correlation coefficient matrix for the coefficients in the model. |

`cov.unscaled` |
The unscaled covariance matrix; i.e, a matrix such that multiplying it by an estimate of the error variance produces an estimated covariance matrix for the coefficients. |

`sigma` |
The scale estimate. |

`stddev` |
A scale estimate used for the standard errors. |

`df` |
The number of degrees of freedom for the model and for residuals. |

`coefficients` |
A matrix with three columns, containing the coefficients, their standard errors and the corresponding t statistic. |

`terms` |
The terms object used in fitting this model. |

### References

Venables, W. N. and Ripley, B. D. (2002)
*Modern Applied Statistics with S.* Fourth edition. Springer.

### See Also

### Examples

```
summary(rlm(calls ~ year, data = phones, maxit = 50))
```

*MASS*version 7.3-60.2 Index]