**Parent Command**

any third-level command in block `> OBSERVATION`

**Subcommand**

none

**Description**

This command sets the autoregression coefficient *rho* for a data set.
To partially account for time correlations, a first-order autogregressive time series model (AR1) can be applied to the residuals:

The first-order autoregressive should be applied to time series only if the sampling interval is approximately constant. The autoregression coefficient

**Example**

`
> OBSERVATION
>> PRESSURE
>>> ELEMENT : A1125
>>>> Read DATA from FILE : pres.col
>>>> standard DEVIATION : 200.0 Pa
>>>> REGRESSION : 0.1
<<<<
<<<
`

**See Also**`
>> REGRESSION,
>>>> SHIFT
`

Page updated: January 4, 2010