This calculator computes the Sobel test statistic and p-value to assess the significance of the indirect effect in mediation analysis. Enter the path coefficients (a, b) and their standard errors to determine whether the mediated effect is statistically significant. For critical decisions, confirm results with professional statistical software.

Sobel Test Calculator for Mediation

Enter the coefficients and standard errors to assess the significance of the mediation effect.

* Note: The Sobel test examines the significance of the indirect effect $a \times b$.

Step 1: Enter Parameters

Coefficient $ a $:

Effect of the independent variable on the mediator.

Standard Error of $ a $ ($ s_a $):

Standard error for the $ a $ coefficient.

Coefficient $ b $:

Effect of the mediator on the dependent variable.

Standard Error of $ b $ ($ s_b $):

Standard error for the $ b $ coefficient.

How It Works

The Sobel test statistic is computed as: $$ z = \frac{a \times b}{\sqrt{b^2 \, s_a^2 + a^2 \, s_b^2}}. $$

The resulting z value is compared to the standard normal distribution to obtain the two‑tailed p‑value.

Step 1: Enter Parameters

Sobel Test Results

How It Works