Mean group size for each row

For a grouping vector or a matrix of groupings (such as the output of tile_groups(), with one column per randomization), returns the average number of members in each element's group. With a groups matrix, this is the average over columns. It describes the size of the pool each row (e.g. site) is randomized within, and depends only on the grouping, so it can be checked before running any randomizations, for example while choosing a tile spacing. Rows that are often in very small groups are rarely changed by a fixed-margin randomization; a row alone in its group is never changed.

Usage

group_sizes(groups)

Arguments

groups

A vector of group labels, or a matrix of group labels with one column per randomization.

Value

A numeric vector with one value per element (row) of groups.

See also

tile_groups()

Examples

group_sizes(c("a", "a", "b", "c", "c", "c"))
#> [1] 2 2 1 3 3 3

set.seed(1)
coords <- cbind(runif(200, 0, 10), runif(200, 0, 10))
g <- tile_groups(coords, spacing = 3, n = 50, lonlat = FALSE)
summary(group_sizes(g))
#>    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
#>    2.88   12.46   15.18   15.05   18.02   22.72