# Demonstration for the stratified sampling

### Description

Each rectangle stands for a stratum, and the simple random sampling without replacement is performed within each stratum. The points being sampled are marked out (by red circles by default).

### Usage

1 2 3 |

### Arguments

`pop` |
a vector for the size of each stratum in the population. |

`size` |
a corresponding vector for the sample size in each stratum (recycled if necessary). |

`p.col, p.cex` |
different colors /magnification rate to annotate the population and the sample |

`...` |
other arguments passed to |

### Value

None (invisible '`NULL`

').

### Author(s)

Yihui Xie

### See Also

`sample`

, `sample.simple`

,
`sample.cluster`

, `sample.ratio`

,
`sample.system`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | ```
oopt = ani.options(nmax = ifelse(interactive(), 50, 2))
par(mar = rep(1, 4), lwd = 2)
sample.strat(col = c("bisque", "white"))
## HTML animation page
saveHTML({
par(mar = rep(1, 4), lwd = 2)
ani.options(nmax = ifelse(interactive(), 50, 2))
sample.strat(col = c("bisque", "white"))
}, img.name = "sample.strat", htmlfile = "sample.html", ani.height = 350,
ani.width = 500, title = "Demonstration of the stratified sampling",
description = c("Every rectangle stands for a stratum, and the simple",
"random sampling without replacement is performed within each stratum."))
ani.options(oopt)
``` |