# plotmeans: Plot Group Means and Confidence Intervals In gplots: Various R Programming Tools for Plotting Data

## Description

Plot group means and confidence intervals.

## Usage

 ```1 2 3 4 5 6 7 8``` ```plotmeans(formula, data=NULL, subset, na.action, bars=TRUE, p=0.95, minsd=0, minbar, maxbar, xlab=names(mf)[2], ylab=names(mf)[1], mean.labels=FALSE, ci.label=FALSE, n.label=TRUE, text.n.label="n=", digits=getOption("digits"), col="black", barwidth=1, barcol="blue", connect=TRUE, ccol= col, legends=names(means), xaxt, use.t=TRUE, lwd=par("lwd"), ...) ```

## Arguments

 `formula` symbolic expression specifying the outcome (continuous) and grouping variable (factor). See lm() for details. `data` optional data frame containing the variables in the model. `subset` an optional vector specifying a subset of observations to be used in the fitting process. `na.action` a function which indicates what should happen when the data contain ‘NA’s. See lm() for details. `bars` a logical value indicating whether confidence interval bars should be plotted. Defaults to TRUE. `p` confidence level for error bars. Defaults to 0.95. `minsd` minumum permitted value for the standard deviation within each factor level. Any standard deviation estimates smaller than `minsd` will be replaced with `minsd`. Defaults to 0. `minbar` minumum allowed value for bar ends. If specified, values smaller than `minbar` will be replaced with `minbar`. `maxbar` maximum allowed value for bar ends. If specified, values larger than `maxbar` will be replaced with `maxbar`. `xlab` x-axis label. `ylab` y-axis label. `mean.labels` either a logical value indicating whether the circles representing the group means should be replaced with text giving the actual mean values or a vector containing labels to use instead. Defaults to FALSE. `ci.label` a logical value indicating whether text giving the actual interval end values should be placed at the end of each confidence interval bar. Defaults to FALSE. `n.label` a logical value indicating whether text giving the number of observations in each group should should be added to the plot. `text.n.label` Prefix text for labeling observation counts. Defaults to "n=". `digits` number of significant digits to use when displaying mean or confidince limit values. `col` color of cicles marking group means. Default is "black". `barwidth` linewidth of interval bars and end marks. Default is 1. `barcol` color of interval bars and end marks. Default is "blue". `connect` either a logical value indicating whether the means of each group should be connected by a line, or a list of vectors giving the index of bars that should be connected by a line. Defaults to TRUE. `ccol` color of lines used to connect means. Defaults to the same color as "col". `legends` vector containing strings used to label groups along the x axis. Defaults to group names. `xaxt` A character which specifies the axis type. Specifying ‘"n"’ causes an axis to be set up, but not plotted. `use.t` a logical value indicating whether the t distribution should be used to compute confidence intervals. If `TRUE`, the default, a t distribution will the correct number of degrees of freedom for each group be used. If `FALSE`, the a normal distribution will be used. `lwd` Width of connecting lines `...` optional plotting parameters.

## Author(s)

Gregory R. Warnes [email protected]

`plotCI`, `boxplot`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30``` ``` # show comparison with boxplot data(state) plotmeans(state.area ~ state.region) # show some color and mean labels plotmeans(state.area ~ state.region, mean.labels=TRUE, digits=-3, col="red", connect=FALSE) # show how to specify which means should be connected plotmeans(state.area ~ state.region, connect=list(1:2, 3:4), ccol="red", pch=7 ) # more complicated example showing how to show an interaction data(esoph) par(las=2, # use perpendicular axis labels mar=c(10.1,4.1,4.1,2.1), # create enough space for long x labels mgp=c(8,1,0) # move x axis legend down to avoid overlap ) plotmeans(ncases/ncontrols ~ interaction(agegp , alcgp, sep =" "), connect=list(1:6,7:12,13:18,19:24), barwidth=2, col="dark green", data=esoph, xlab="Age Group and Alcohol Consumption", ylab="# Cases / # Controls", main=c("Fraction of Cases for by Age and Alcohol Consumption", "Ile-et-Vilaine Esophageal Cancer Study") ) abline(v=c(6.5, 12.5, 18.5), lty=2) ```