s. Path a represents the effect of X on the proposed mediator, whereas path b is the effect of M on Y partialling out the effect of X. The indirect effect of X on Y through M can then be quantified as the product of a and b (i.e., ab). The total effect of X on Y can be expressed as the sum of the direct and indirect effects: c = c′+ab. Equivalently, c′ is the difference between the total effect of X on Y and the indirect effect of X on Y through M, that is, c′ = c-ab ([@B00], p. 000).](fpsyg-00-00000-g000){#F0}  