Computes the selection differential S = Cov(z, w) for a single trait.
Usage
selection_differential(
data,
fitness_col,
trait_col,
standardized = TRUE,
use_relative = TRUE,
group = NULL,
return_grouped = FALSE
)Arguments
- data
A data frame containing fitness and trait measurements.
- fitness_col
A string specifying the name of the fitness column.
- trait_col
A string specifying the name of the trait column.
- standardized
Logical indicating whether the trait is already standardized. If
FALSE, it will be standardized.- use_relative
Logical indicating whether to use relative fitness.
- group
Optional grouping variable string. Calculates S within each group if provided.
- return_grouped
Logical indicating whether to return a data frame with S per group (
TRUE) or overall mean S (FALSE).
Value
A single numeric value representing overall S, or a data frame with S per group if return_grouped = TRUE.
Examples
prep <- prepare_selection_data(bumpus, "survival", "total_length")
selection_differential(prep, "survival", "total_length")
#> [1] -0.2347161
selection_differential(prep, "survival", "total_length", group = "sex", return_grouped = TRUE)
#> # A tibble: 2 × 3
#> sex S n
#> <fct> <dbl> <int>
#> 1 female -0.168 49
#> 2 male -0.329 87