# studpermu.test

##### Studentised Permutation Test

Perform a studentised permutation test for a difference between groups of point patterns.

##### Usage

```
studpermu.test(X, formula, summaryfunction = Kest,
..., rinterval = NULL, nperm = 999,
use.Tbar = FALSE, minpoints = 20, rsteps = 128,
r = NULL, arguments.in.data = FALSE)
```

##### Arguments

- X
- Data. Either a
`hyperframe`

or a list of lists of point patterns. - formula
- Formula describing the grouping, when
`X`

is a hyperframe. The left side of the formula identifies which column of`X`

contains the point patterns. The right side identifies the grouping factor. If the formula is mis - summaryfunction
- Summary function applicable to point patterns.
- ...
- Additional arguments passed to
`summaryfunction`

. - rinterval
- Interval of distance values $r$ over which the
summary function should be evaluated and over which the test
statistic will be integrated. If
`NULL`

, the default range of the summary statistic is used (taking the intersection of - nperm
- Number of random permutations for the test.
- use.Tbar
- Logical value indicating choice of test statistic.
If
`TRUE`

, use the alternative test statistic, which is appropriate for summary functions with roughly constant variance, such as $K(r)/r$ or $L(r)$. - minpoints
- Minimum permissible number of points in a point pattern for inclusion in the test calculation.
- rsteps
- Number of discretisation steps in the
`rinterval`

. - r
- Optional vector of distance values as the argument for
`summaryfunction`

. Should not usually be given. There is a sensible default. - arguments.in.data
- Logical. If
`TRUE`

, individual extra arguments to`summaryfunction`

will be taken from`X`

(which must be a hyperframe). This assumes that the first argument of`summaryfunction`

is the point pa

##### Details

This function performs the studentized permutation test of Hahn (2012) for a difference between groups of point patterns.

The first argument `X`

should be either
[object Object],[object Object]
A group needs to contain at least two point patterns with at least
`minpoints`

points in each pattern.

The function returns an object of class `"htest"`

and `"studpermutest"`

that can be printed and plotted.
The printout shows the test result and $p$-value.
The plot shows the summary functions for the
groups (and the group means if requested).

##### Value

- Object of class
`"studpermutest"`

.

##### References

Hahn, U. (2012)
A studentized permutation test for the comparison of
spatial point patterns.
*Journal of the American Statistical Association*
**107** (498), 754--764.

##### Examples

`testpyramidal <- studpermu.test(pyramidal, Neurons ~ group)`

*Documentation reproduced from package spatstat, version 1.42-2, License: GPL (>= 2)*