errorsINx {DAAG} | R Documentation |

## Simulate data for straight line regression, with "errors in x".

### Description

Simulates $y-$ and $x-$values for the straight line regression model, but with $x-$values subject to random measurement error, following the classical “errors in x” model. Optionally, the x-values can be split into two groups, with one group shifted relative to the other

### Usage

```
errorsINx(mu = 12.5, n = 200, a = 15, b = 1.5, SDx=2, SDyerr = 1.5,
timesSDx=(1:5)/2.5, gpfactor=if(missing(gpdiff))FALSE else TRUE,
gpdiff=if(gpfactor) 1.5 else 0, layout=NULL,
parset = simpleTheme(alpha = 0.75, col = c("black","gray45"),
col.line = c("black","gray45"), lwd=c(1,1.5), pch=c(1,2),
lty=c(1,2)), print.summary=TRUE, plotit=TRUE, xrelation="same")
```

### Arguments

`mu` |
Mean of $z$ |

`n` |
Number of points |

`a` |
Intercept in model where $z$ is measured without error |

`b` |
Slope in model where $z$ is measured without error |

`SDx` |
SD of $z$-values, measured without error |

`SDyerr` |
SD of error term in |

`timesSDx` |
SD of measurement error is |

`gpfactor` |
Should x-values be split into two groups, with one shifted relative to the other? |

`gpdiff` |
Amount of shift of one group of z-values relative to the other |

`layout` |
Layout for lattice graph, if requested |

`parset` |
Parameters to be supplied to the lattice plot, if any |

`print.summary` |
Print summary information on fits? |

`plotit` |
logical: plot the data? |

`xrelation` |
character: sets the x-axis |

### Details

The argument `timesSDx`

can be a numeric vector.
One set of $x$-values that are contaminated with measurement error
is simulated for each element of `timesSDx`

.

### Value

`gph` |
the trellis graphics object |

`mat` |
A matrix, with |

### Author(s)

John Maindonald

### References

Data Analysis and Graphics Using R, 3rd edn, Section 6.7

### Examples

```
library(lattice)
errorsINx()
errorsINx(gpdiff=2, timesSDx=1.25, SDyerr=2.5, n=80)
```

*DAAG*version 1.25.6 Index]