bplot {asbio} | R Documentation |

## Barplots with error bars (including interval plots)

### Description

Creates barplots for displaying statistical summaries by treatment (e.g. means, medians, *M*-estimates of location, standard deviation, variance, etc.) and
their error estimates by treatment (i.e. standard errors, confidence intervals, *IQR*s, *IQR* confidence intervals, and *MAD* intervals). Custom intervals can also be created.
The function can also be used to display letters indicating if comparisons of locations are significant after adjustment for simultaneous inference (see `pairw.anova`

, `pairw.kw`

, and/or `pairw.fried`

).

### Usage

```
bplot(y, x, bar.col = "gray", loc.meas = mean, sort = FALSE, order = NULL, int = "SE",
conf = 0.95, uiw = NULL, liw = NULL, sfrac = 0.1, slty = 1, scol = 1,
slwd = 1, exp.fact = 1.5, simlett = FALSE, lett.side = 3, lett = NULL,
cex.lett = 1, names.arg = NULL, ylim = NULL, horiz = FALSE, xpd = FALSE,
print.summary = TRUE, ...)
```

### Arguments

`y` |
A quantitative vector representing the response variable. |

`x` |
A categorical vector representing treatments (e.g. factor levels). |

`bar.col` |
Color of bar. |

`loc.meas` |
Measure of location or other summary statistic, e.g. mean, median, etc. |

`sort` |
Logical, if |

`order` |
A vector of length equal to the number of factor levels, specifying the order of bars with respect to the alphanumeric order of their names. |

`int` |
Type of error bar to be drawn, must be one of |

`conf` |
Level of confidence, 1 - |

`uiw` |
Upper |

`liw` |
Lower |

`sfrac` |
Scaling factor for the size of the "serifs" (end bars) on the confidence bars, in |

`slty` |
Line type for error bars. |

`scol` |
Line color for error bars. |

`slwd` |
Line width for error bars. |

`exp.fact` |
A multiplication factor indicating how much extra room is made for drawing letters in top of graph. Only used if |

`simlett` |
A logical statement indicating whether or not letters should be shown above bars indicating that populations means have been determined to be significantly different. |

`lett.side` |
Side that letters will be drawn on, 1 = bottom, 2 = left, 3 = top, 4 = right. |

`lett` |
A vector of letters or some other code to display multiple comparison results. |

`cex.lett` |
Character expansion for multiple comparison result letters. |

`names.arg` |
A vector of names to be plotted below each bar or error bar. If this argument is omitted, then the names are taken from the names attribute of |

`ylim` |
Upper and lower limits of the |

`horiz` |
Logical value. If |

`xpd` |
Logical value. If |

`print.summary` |
Logical value. If |

`...` |
Additional arguments from |

### Details

It is often desirable to display the results of a pairwise comparison procedure using sample measures of location and error bars. This functions allows these sorts of plots to be made. The function is essentially a wrapper for the function `barplot`

.

### Value

A plot is returned. Bar centers (ala `barplot`

) are returned invisibly.

### Author(s)

Ken Aho

### References

Chambers, J. M., Cleveland, W. S., Kleiner, B. and Tukey, P. A. (1983) *Graphical Methods for Data Analysis*. Wadsworth & Brooks/Cole.

McGill, R., Tukey, J. W. and Larsen, W. A. (1978) Variations of box plots. *The American Statistician* 32, 12-16.

### See Also

`mad`

, `barplot`

, `pairw.anova`

, `pairw.kw`

, `pairw.fried`

### Examples

```
eggs<-c(11,17,16,14,15,12,10,15,19,11,23,20,18,17,27,33,22,26,28)
trt<-c(1,1,1,1,1,2,2,2,2,2,3,3,3,3,4,4,4,4,4)
bplot(y=eggs, x=factor(trt),int="SE",xlab="Treatment",ylab="Mean number of eggs",
simlett=TRUE, lett=c("b","b","b","a"))
```

*asbio*version 1.9-7 Index]