Specify covariance for a means-based unbalanced design — unbalanced

Defines the common marginal standard deviation and within-subject correlation structure used by power_unbalanced(). The resulting covariance is shared by every between-subject cell.

Usage

unbalanced_covariance(sd = 1, default_correlation = 0.5, correlations = NULL)

Arguments

sd: Common positive finite marginal standard deviation. If omitted, 1 is used and a warning is issued.
default_correlation: Correlation in (-1, 1) used for unlisted pairs. When the specification is resolved for a design, a warning identifies how many pairs were not defined and makes clear that this default applies only to those pairs.
correlations: Optional named numeric vector of pair-specific correlations. Name pairs as "cell1:cell2"; pair order does not matter. For multiple within factors, cell names join their level values with _. Constructed names must be unique, and level values must not contain : because it separates the two cells in a pair name.

Value

An anovapowersim_unbalanced_covariance_spec object.

Lifecycle

unbalanced_covariance() is experimental and is available only in the development version of anovapowersim. Its API may change.

Examples

unbalanced_covariance(
  sd = 2,
  default_correlation = 0.5,
  correlations = c("pre:post" = 0.7)
)
#> $sd
#> [1] 2
#> 
#> $default_correlation
#> [1] 0.5
#> 
#> $correlations
#> pre:post 
#>      0.7 
#> 
#> $correlation_pairs
#> # A tibble: 1 × 4
#>   pair_name cell1 cell2 pair_key   
#>   <chr>     <chr> <chr> <chr>      
#> 1 pre:post  pre   post  "post\rpre"
#> 
#> attr(,"class")
#> [1] "anovapowersim_unbalanced_covariance_spec"