df.WS {BivRegBLS} | R Documentation |

## Degrees of freedom by Welch-Satterthwaite

### Description

Calculate the degrees of freedom from the Welch-Satterthwaite equation for a linear combination of sample variances.

### Usage

```
df.WS(variances = NULL, k = rep(1, length(variances)), dfs = NULL)
```

### Arguments

`variances` |
a numeric vector for the variances. |

`k` |
a numeric vector with the multiplicative constants. |

`dfs` |
a numeric vector with the degrees of freedom of each variance. |

### Details

The `variances`

argument is mandatory while other arguments are optional.

### Value

A numeric variable with the degrees of freedom of the linear combination of the variances.

### Author(s)

Bernard G FRANCQ

### References

Satterthwaite FE. An Approximate Distribution of Estimates of Variance Components. Biometrics Bulletin, 1946, 2: 110-114.

Welch BK. The generalization of "student's" problem when several different population variances are involved. Biometrika, 1947, 34: 28-35.

### Examples

```
df.WS(variances=c(10,15,20),k=c(1.5,2,1.3),dfs=c(8,13,11))
```

[Package

*BivRegBLS*version 1.1.1 Index]