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
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/quincunx.R, R/quincunx2.R
\name{quincunx}
\alias{quincunx}
\alias{quincunx2}
\title{Demonstration of the Quincunx (Bean Machine/Galton Box)}
\usage{
quincunx(
balls = 200,
layers = 15,
pch.layers = 2,
pch.balls = 19,
col.balls = sample(colors(), balls, TRUE),
cex.balls = 2
)
quincunx2(
balls = 200,
layers = 15,
pch.layers = 2,
pch.balls = 19,
col.balls = sample(colors(), balls, TRUE),
cex.balls = 2
)
}
\arguments{
\item{balls}{number of balls}
\item{layers}{number of layers}
\item{pch.layers}{point character of layers; triangles (\code{pch = 2}) are
recommended}
\item{pch.balls, col.balls, cex.balls}{point character, colors and
magnification of balls}
}
\value{
A named vector: the frequency table for the locations of the balls.
Note the names of the vector are the locations: 1.5, 2.5, ..., layers -
0.5.
}
\description{
Simulates the quincunx with ``balls'' (beans) falling through several layers
(denoted by triangles) and the distribution of the final locations at which
the balls hit is denoted by a histogram; \code{quincunx()} is shows single
layer, and \code{quincunx2()} is a two-stage version of the quincunx.
}
\details{
The bean machine, also known as the quincunx or Galton box, is a device
invented by Sir Francis Galton to demonstrate the law of error and the normal
distribution.
When a ball falls through a layer, it can either go to the right or left side
with the probability 0.5. At last the location of all the balls will show us
the bell-shaped distribution.
}
\note{
The maximum number of animation frames is controlled by
\code{ani.options('nmax')} as usual, but it is strongly recommended that
\code{ani.options(nmax = balls + layers -2)}, in which case all the balls
will just fall through all the layers and there will be no redundant
animation frames.
}
\references{
Examples at \url{https://yihui.org/animation/example/quincunx/}
}
\seealso{
\code{\link{rbinom}}
}
\author{
Yihui Xie, Lijia Yu, and Keith ORourke
}
|
