corgen: Generate correlated data In ecodist: Dissimilarity-Based Functions for Ecological Analysis

Description

Generate correlated data of a given length.

Usage

 `1` ``` corgen(len, x, r, population = FALSE, epsilon = 0) ```

Arguments

 `len` Length of vectors. `x` Independent data. If x is specified, the population parameter is automatically set to TRUE. `r` Desired correlation between data vectors. `population` TRUE for vectors drawn from two populations with correlation r, otherwise r is the sample correlation. `epsilon` Desired tolerance.

Details

Either x or len must be specified. If epsilon = 0, it has no effect, otherwise the sampling process is repeated until the sample correlation is within epsilon of r. This option allows the production of exactly-correlated data, within the limits of epsilon. Setting epsilon > 0 invalidates the population setting; data will be correlated within that range, rather than sampled from that population.If epsilon = 0, it has no effect, otherwise the sampling process is repeated until the sample correlation is within epsilon of r. This option allows the production of exactly-correlated data, within the limits of epsilon. Setting epsilon > 0 invalidates the population setting; data will be correlated within that range, rather than sampled from that population.If epsilon = 0, it has no effect, otherwise the sampling process is repeated until the sample correlation is within epsilon of r. This option allows the production of exactly-correlated data, within the limits of epsilon. Setting epsilon > 0 invalidates the population setting; data will be correlated within that range, rather than sampled from that population.

Value

 `x ` First data vector, either generated by corgen or given by the user. `y ` Second data vector.

Sarah Goslee

Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14``` ```# create two random variables of length 100 with correlation # of 0.10 +/- 0.01 xy <- corgen(len=100, r=.1, epsilon=0.01) with(xy, cor(x, y)) # create two random variables of length 100 drawn from a population with # a correlation of -0.82 xy <- corgen(len=100, r=-0.82, population=TRUE) with(xy, cor(x, y)) # create a variable y within 0.01 of the given correlation to x x <- 1:100 y <- corgen(x=x, r=.5, epsilon=.01)\$y cor(x, y) ```

ecodist documentation built on July 13, 2017, 9:02 a.m.