R: Perception of points in a swarm

rainman {MESS} | R Documentation

## Perception of points in a swarm

### Description

Five raters were asked to guess the number of points in a swarm for 10 different figures (which - unknown to the raters - were each repeated three times).

### Format

A data frame with 30 observations on the following 6 variables.

SAND

  The true number of points in the swarm. Each picture is replicated thrice

ME

  Ratings from judge 1

TM

  Ratings from judge 2

AJ

  Ratings from judge 3

BM

  Ratings from judge 4

LO

  Ratings from judge 5

### Details

The raters har approximately 10 seconds to judge each picture, and the thought it was 30 different pictures. Before starting the experiment they were shown 6 (unrelated) pictures and were told the number of points in each of those pictures. The SAND column contains the picture id and the true number of points in the swarm.

### Source

Collected by Claus Ekstrom.

### Examples

    data(rainman)
    long <- data.frame(stack(rainman[,2:6]), figure=factor(rep(rainman$SAND,5)))
    figind <- interaction(long$figure,long$ind)
    # Use a linear random effect model from the
    # lme4 package if available
    if(require(lme4)) {
      model <- lmer(values ~ (1|ind) + (1|figure) + (1|figind), data=long)
    }

    #
    # Point swarms were generated by the following program
    #
    ## Not run:
    set.seed(2) # Original
    npoints <- sample(4:30)*4
    nplots <- 10
    pdf(file="swarms.pdf", onefile=TRUE)

    s1 <- sample(npoints[1:nplots])
    print(s1)
    for (i in 1:nplots) {
      n <- s1[i]
      set.seed(n)
      x <- runif(n)
      y <- runif(n)
      plot(x,y, xlim=c(-.15, 1.15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
           xlab="", ylab="")
    }
    s1 <- sample(npoints[1:nplots])
    print(s1)
    for (i in 1:nplots) {
      n <- s1[i]
      set.seed(n)
      x <- runif(n)
      y <- runif(n)
      plot(y,x, xlim=c(-.15, 1.15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
           xlab="", ylab="")
    }
    s1 <- sample(npoints[1:nplots])
    print(s1)
    for (i in 1:nplots) {
      n <- s1[i]
      set.seed(n)
      x <- runif(n)
      y <- runif(n)
      plot(-x,y, xlim=c(-1.15, .15), ylim=c(-.15, 1.15), pch=20, axes=FALSE,
           xlab="", ylab="")
    }
    dev.off()

    ## End(Not run)

[Package MESS version 0.5.6 Index]