interaction_params {simpr.interaction}R Documentation

Extract simulation parameters for power analysis of regression interaction models.

Description

Extract useful simulation parameters for regression.interaction models, computed via change in R2. This function is largely a wrapper for power_interaction_r2() from the InteractionPoweR package which calculates useful quantities based on correlations and reliabilities. This function then massages the output into a more convenient format for simpr as well as calculating R2 and sigma.

Usage

interaction_params(
  r.x1.y,
  r.x2.y,
  r.x1x2.y,
  r.x1.x2,
  rel.x1 = 1,
  rel.x2 = 1,
  rel.y = 1
)

Arguments

r.x1.y

Pearson's correlation between x1 and y. Must be between -1 and 1.

r.x2.y

Pearson's correlation between x2 and y. Must be between -1 and 1. Assumed to be the 'moderator' in some functions.

r.x1x2.y

Pearson's correlation between the interaction term x1x2 (x1 * x2) and y. Must be between -1 and 1.

r.x1.x2

Pearson's correlation between x1 and x2. Must be between -1 and 1. Has no default value.

rel.x1

Reliability of x1 (e.g. test-retest reliability, ICC, Cronbach's alpha). Default is 1 (perfect reliability). Must be greater than 0 and less than or equal to 1.

rel.x2

Reliability of x2 (e.g. test-retest reliability, ICC, Cronbach's alpha). Default is 1 (perfect reliability). Must be greater than 0 and less than or equal to 1.

rel.y

Reliability of y (e.g. test-retest reliability, ICC, Cronbach's alpha). Default is 1 (perfect reliability). Must be greater than 0 and less than or equal to 1.

Value

A list with the following elements:

b1:

Slope for simulation of x1

b2:

Slope for simulation of x2

b3:

Slope for simulation of x1:x2

obs.r.x1.x2:

Adjusted correlation of x1 and x2

obs.r.x1.y:

Adjusted correlation of x1 and y

obs.r.x2.y:

Adjusted correlation of x1 and y

obs.r.x1x2.y:

Adjusted correlation of x1:x2 and y

r2:

R-squared

sigma:

Sigma

cov:

Adjusted correlation matrix of x1 and x2

Examples

params_all = interaction_params(r.x1.y = -0.18,
 r.x2.y = -0.03,
 r.x1.x2 = 0.64,
 r.x1x2.y = 0.1,
 rel.y = 0.79,
 rel.x1 = 0.89,
 rel.x2 = 0.95)

[Package simpr.interaction version 0.1.0 Index]