Confounding, interaction, and mediation in multivariable/multivariate ...
Confounding, interaction, and mediation in multivariable/multivariate ...
Confounding, interaction, and mediation in multivariable/multivariate ...
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Mediation<br />
<strong>Confound<strong>in</strong>g</strong><br />
Interaction<br />
3 examples<br />
Def<strong>in</strong>ition <strong>and</strong> identification<br />
An application<br />
Approach 2: statistical test of <strong>mediation</strong><br />
Sobel test:<br />
to test the products√<br />
of coefficients of the two paths a <strong>and</strong> b.<br />
z − value = α ∗ β/ α 2 σβ 2 + β2 σα<br />
2<br />
The null hypothesis is a test of α ∗ β = 0.<br />
MacK<strong>in</strong>non <strong>and</strong> Dwyer (1994) <strong>and</strong> MacK<strong>in</strong>non, Warsi, <strong>and</strong> Dwyer (1995)<br />
logo<br />
William Wu<br />
Cancer Biostatistics
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