# plot.rqs

##### Visualizing sequences of quantile regressions

A sequence of coefficient estimates for quantile
regressions with varying `tau`

parameters is visualized.

- Keywords
- hplot

##### Usage

```
# S3 method for rqs
plot(x, parm = NULL, ols = TRUE,
mfrow = NULL, mar = NULL, ylim = NULL, main = NULL, col = 1:2, lty = 1:2,
cex = 0.5, pch = 20, type = "b", xlab = "", ylab = "", …)
```

##### Arguments

- x
an object of class

`"rqs"`

as produce by`rq`

(with a vector of`tau`

values).- parm
a specification of which parameters are to be plotted, either a vector of numbers or a vector of names. By default, all parameters are considered.

- ols
logical. Should a line for the OLS coefficient (as estimated by

`lm`

) be added?- mfrow, mar, ylim, main
graphical parameters. Suitable defaults are chosen based on the coefficients to be visualized.

- col, lty
graphical parameters. For each parameter, the first element corresponds to the

`rq`

coefficients and the second to the`lm`

coefficients.- cex, pch, type, xlab, ylab, …
further graphical parameters passed to

`plot`

.

##### Details

The `plot`

method for `"rqs"`

objects visualizes the
coefficients only, confidence bands can be added by using the `plot`

method for the associated `"summary.rqs"`

object.

##### Value

A matrix with all coefficients visualized is returned invisibly.

##### See Also

##### Examples

```
# NOT RUN {
## fit Engel models (in levels) for tau = 0.1, ..., 0.9
data("engel")
fm <- rq(foodexp ~ income, data = engel, tau = 1:9/10)
## visualizations
plot(fm)
plot(fm, parm = 2, mar = c(5.1, 4.1, 2.1, 2.1), main = "", xlab = "tau",
ylab = "income coefficient", cex = 1, pch = 19)
# }
```

*Documentation reproduced from package quantreg, version 5.54, License: GPL (>= 2)*