backPain | R Documentation |

Data from a study of patients suffering from back pain. Prognostic variables were recorded at presentation and progress was categorised three weeks after treatment.

`data(backPain)`

A data frame with 101 observations on the following 4 variables.

- x2
length of previous attack.

- x3
pain change.

- x4
lordosis.

- pain
an ordered factor describing the progress of each patient with levels

`worse`

<`same`

<`slight.improvement`

<`moderate.improvement`

<`marked.improvement`

<`complete.relief`

.

`http://ideas.repec.org/c/boc/bocode/s419001.html`

The data set and this help file was copied from gnm so that a vignette in VGAM could be run; the analysis is described in Yee (2010).

The data frame `backPain2`

is a modification of
`backPain`

where the variables have been renamed
(`x1`

becomes `x2`

,
`x2`

becomes `x3`

,
`x3`

becomes `x4`

)
and
converted into factors.

Anderson, J. A. (1984).
Regression and Ordered Categorical Variables.
*J. R. Statist. Soc. B*, **46(1)**, 1-30.

Yee, T. W. (2010).
The VGAM package for categorical data analysis.
*Journal of Statistical Software*,
**32**, 1–34.
\Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v032.i10")}.

```
summary(backPain)
summary(backPain2)
```

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