adehabitatLT (version 0.1)

wawotest: Wald-Wolfowitz Test of Randomness

Description

The function wawotest.default performs a Wald Wolfowitz test of the random distribution of the values in a vector. The function wawotest.ltraj performs this tests for the descriptive parameters dx, dy and dist in an object of class ltraj. The function wawotest is generic.

Usage

wawotest(x, ...)
## S3 method for class 'default':
wawotest(x, alter = c("greater", "less"), ...)
## S3 method for class 'ltraj':
wawotest(x, \dots)

Arguments

x

for wawotest.default

alter

a character string specifying the alternative hypothesis, must be one of "greater" (default), "less" or "two-sided"

...

additional arguments to be passed to other functions

Value

• wawotest.default returns a vector containing the value of the statistic (a), its esperance (ea), its variance (va), the normed statistic (za) and the P-value. wawotest.ltraj returns a table giving these values for the descriptive parameters of the trajectory.

Details

The statistic of the test is equal to A = sum(y(i) y(i+1)), with y(N+1) = y(1). Under the hypothesis of a random distribution of the values in the vector, this statistic is normally distributed, with theoretical means and variances given in Wald & Wolfowitz (1943).

References

Wald, A. & Wolfowitz, J. (1943) An exact test for randomness in the non-parametric case based on serial correlation. Ann. Math. Statist., 14, 378--388.

See Also

indmove and runsNAltraj for other tests of independence to be used with objects of class "ltraj"

Examples

data(puechcirc)
puechcirc
wawotest(puechcirc)