heplots (version 1.2-0)

ReactTime: Reaction Time Data

Description

Data from Maxwell and Delaney (1990, p. 497) representing the reaction times of 10 subjects in some task where visual stimuli are tilted at 0, 4, and 8 degrees; with noise absent or present. Each subject responded to 3 tilt x 2 noise = 6 conditions. The data thus comprise a repeated measure design with two within-S factors.

Usage

data(ReactTime)

source

Baron, J. and Li, Y. (2003). Notes on the use of R for psychology experiments and questionnaires, http://cran.r-project.org/doc/contrib/Baron-rpsych.pdf

References

Michael Friendly (2010). HE Plots for Repeated Measures Designs. Journal of Statistical Software, 37(4), 1-40. URL http://www.jstatsoft.org/v37/i04/. Maxwell, S. E. & Delaney, H. D. (1990). Designing Experiments and Analyzing Data: A model comparison perspective. Pacific Grove, CA: Brooks/Cole.

Examples

data(ReactTime)
(RT.mod <- lm(as.matrix(ReactTime)~1))

# within-S factors
within <- expand.grid(tilt=ordered(c(0,4,8)), noise=c("NA", "NP"))
Anova(RT.mod, idata=within, idesign=~tilt * noise)

heplot(RT.mod, idata=within, idesign=~tilt * noise, iterm="tilt")

# plotting means and std errors directly

levels <- expand.grid(Tilt=c(0,4,8), noise=c("NA", "NP"))
(means.df <- data.frame(levels, mean=colMeans(ReactTime), se=sqrt(diag(var(ReactTime)))/9))

with(means.df, {
	plot(Tilt, mean, type="n", main="Reaction Time data", xlab="Tilt", ylab="Reaction time")
	colors <- rep(c("red", "blue"), each=3)
	pts <- rep(c(15, 16), each=3)

	lines(Tilt[1:3], mean[1:3], col="red", lwd=2)
	lines(Tilt[4:6], mean[4:6], col="blue", lwd=2)
	points(Tilt, mean, pch=pts, col=colors, cex=1.2)
	arrows(Tilt, mean-se, Tilt, mean+se, angle=90, code=3, 
			col=colors, len=.05, lwd=2)
	# labels at last point, in lieu of legend
	text(Tilt[3], mean[3]-10, labels="NA", col="red", pos=1)
	text(Tilt[6], mean[6]-10, labels="NP", col="blue", pos=1)
	}
	)