Indirect Mediation Effect Variance Calculator
Enter the coefficients \(a\) and \(b\) along with their standard errors \(s_a\) and \(s_b\) to calculate the indirect effect, its variance, and standard error.
* Note: Variance is computed as \(b^2 s_a^2 + a^2 s_b^2\) and Standard Error as \(\sqrt{b^2 s_a^2 + a^2 s_b^2}\).
Step 1: Enter Parameters
Effect of the independent variable on the mediator.
Standard error for coefficient \(a\).
Effect of the mediator on the dependent variable.
Standard error for coefficient \(b\).
How It Works
The indirect effect is calculated as: $$ a \times b. $$
Its variance is approximated by: $$ \text{Var}(a \times b) = b^2 s_a^2 + a^2 s_b^2. $$
The standard error is the square root of the variance: $$ \text{SE} = \sqrt{b^2 s_a^2 + a^2 s_b^2}. $$