# fishkent: Hypothesis test for von Mises-Fisher distribution over Kent... In Directional: A Collection of Functions for Directional Data Analysis

 Hypothesis test for von Mises-Fisher distribution over Kent distribution R Documentation

## Hypothesis test for von Mises-Fisher distribution over Kent distribution

### Description

The null hypothesis is whether a von Mises-Fisher distribution fits the data well, where the altenrative is that Kent distribution is more suitable.

### Usage

``````fishkent(x, B = 999)
``````

### Arguments

 `x` A numeric matrix containing the data as unit vectors in Euclidean coordinates. `B` The number of bootstrap re-samples. By default is set to 999. If it is equal to 1, no bootstrap is performed and the p-value is obtained throught the asymptotic distribution.

### Details

Essentially it is a test of rotational symmetry, whether Kent's ovalness parameter (beta) is equal to zero. This works for spherical data only.

### Value

This is an "htest"class object. Thus it returns a list including:

 `statistic` The test statistic value. `parameter` The degrees of freedom of the test. If bootstrap was employed this is "NA". `p.value` The p-value of the test. `alternative` A character with the alternative hypothesis. `method` A character with the test used. `data.name` A character vector with two elements.

### Author(s)

Michail Tsagris.

R implementation and documentation: Michail Tsagris mtsagris@uoc.gr.

### References

Rivest L. P. (1986). Modified Kent's statistics for testing goodness of fit for the Fisher distribution in small concentrated samples. Statistics & Probability Letters, 4(1): 1–4.

```iagesag, pc.test, vmf.mle, kent.mle ```

### Examples

``````x <- rvmf(100, rnorm(3), 15)
fishkent(x)
fishkent(x, B = 1)
iagesag(x)
``````

Directional documentation built on Oct. 12, 2023, 1:07 a.m.