plotBinResp {FSA}R Documentation

Plots a binary response variable versus a quantitative explanatory variable.

Description

A function to plot a binary response variable versus a quantitative explanatory variable.

Usage

plotBinResp(x, ...)

## Default S3 method:
plotBinResp(x, y, xlab = paste(deparse(substitute(x))),
  ylab = paste(deparse(substitute(y))), plot.pts = TRUE,
  col.pt = "black", transparency = NULL, plot.p = TRUE,
  breaks = 25, p.col = "blue", p.pch = 3, p.cex = 1.25,
  yaxis1.ticks = seq(0, 1, 0.1), yaxis1.lbls = c(0, 0.5, 1),
  yaxis2.show = TRUE, ...)

## S3 method for class 'formula'
plotBinResp(x, data = NULL, xlab = names(mf)[2],
  ylab = names(mf)[1], ...)

Arguments

x

A quantitative explanatory variable or a formula of the form factor~quant.

...

Other arguments to be passed to the plot functions.

y

A binary response variable.

xlab

A string for labeling the x-axis.

ylab

A string for labeling the y-axis.

plot.pts

A logical that indicates (TRUE (default)) whether the points should be plotted (TRUE; default) or not (FALSE).

col.pt

A string used to indicate the color of the plotted points. Will be transparent unless transparency=1.

transparency

A numeric that indicates how many points would be plotted on top of each other before the ‘point’ would have the full col.pt color. The reciprocal of this value is the alpha transparency value.

plot.p

A logical that indicates if the proportion for categorized values of X are plotted (TRUE; default).

breaks

A number that indicates how many intervals over which to compute proportions or a numeric vector that contains the endpoints of the intervals over which to compute proportions if plot.p=TRUE.

p.col

A color to plot the proportions.

p.pch

A plotting character for plotting the proportions.

p.cex

A character expansion factor for plotting the proportions.

yaxis1.ticks

A numeric vector that indicates where tick marks should be placed on the left y-axis (for the proportion of ‘successes’).

yaxis1.lbls

A numeric vector that indicates labels for the tick marks on the left y-axis (for the proportion of ‘successes’).

yaxis2.show

A logical that indicates whether the right y-axis should be created (=TRUE; default) or not.

data

The data frame from which the formula should be evaluated.

Details

This function produces a plot that can be used to visualize the density of points for a binary response variable as a function of a quantitative explanatory variable. In addition, the proportion of “1”s for the response variable at various “levels” of the explanatory variable are shown.

Value

None. However, a plot is produced.

Note

This function is meant to allow newbie students the ability to visualize the data corresponding to a binary logistic regression without getting “bogged-down” in the gritty details of how to produce this plot.

Author(s)

Derek H. Ogle, derek@derekogle.com

See Also

fitPlot and cdplot.

Examples

## NASA space shuttle o-ring failures -- from graphics package
fail <- factor(c(2,2,2,2,1,1,1,1,1,1,2,1,2,1,1,1,1,2,1,1,1,1,1),
levels = 1:2, labels = c("no","yes"))
temperature <- c(53,57,58,63,66,67,67,67,68,69,70,70,70,70,72,73,75,75,76,76,78,79,81)
d <- data.frame(temperature,fail,fail2=factor(fail,levels=c("yes","no")))

## Default plot (using formula notation)
plotBinResp(fail~temperature,data=d)
plotBinResp(fail2~temperature,data=d)

## Controlling where proportions are computed with a sequence in breaks
plotBinResp(fail~temperature,data=d,breaks=seq(50,85,5))

## Controlling where proportions are computed with an integer in breaks
plotBinResp(fail~temperature,data=d,breaks=10)

## Controlling where proportions are computed at each value of x
plotBinResp(fail~temperature,data=d,breaks=NULL)

## Don't plot points, just plot proportions
plotBinResp(fail~temperature,data=d,plot.pts=FALSE)

## Don't plot proportions, just plot points
plotBinResp(fail~temperature,data=d,plot.p=FALSE)

## Change points colors, and eliminate transparency
plotBinResp(fail~temperature,data=d,col.pt="red",transparency=1)

## Remove the right y-axis
plotBinResp(fail~temperature,data=d,yaxis2.show=FALSE)

## Change left y-axis ticks
plotBinResp(fail~temperature,data=d,yaxis1.ticks=c(0,1),yaxis1.lbls=c(0,1))


[Package FSA version 0.8.25.9000 Index]