rao_spacing_test: Rao Spacing Test

Description

Rao's spacing test of uniformity on the circle

Usage

rao_spacing_test(x, alpha = 0.05, n_perm = 9999L, axial = TRUE)

Value

A list with class "htest" containing the following components:

statistic: the value of the L statistic
parameter: the number of data and the number of simulations
p.value: the p-value for the test
alternative: a character string describing the alternative hypothesis.
method: a character string indicating what type of test was performed.
data.name: a character string giving the name(s) of the data.

Arguments

x: numeric vector. Values in degrees
alpha: Significance level of the test ranging between 0 and 1.
n_perm: integer. Number of simulated uniform samples.
axial: logical. Whether the data are axial, i.e. $\pi$-periodical (TRUE, the default) or directional, i.e. $2 \pi$-periodical (FALSE). In case of axial data, the angles will be doubled for the test.

Details

Test statistic is $$L = 1/2 \sum(|T_i - 360 / n|)$$ in degrees, with the spacings $T_i$ between consecutive angles (Mardia & Jupp 2000, eq. 6.3.45). The p-value is the proportion of n_perm simulated uniform samples with a larger $L$

Examples

Run this code

set.seed(20250411)
rao_spacing_test(rvm(100, mean = 0, kappa = 10))

# San Andreas Fault Data:
data(san_andreas)
data("nuvel1")
PoR <- subset(nuvel1, nuvel1$plate.rot == "na")
sa.por <- PoR_shmax(san_andreas, PoR, "right")
rao_spacing_test(sa.por$azi.PoR, alpha = .05)