Figure 4.

These graphical equations algebraically summarize the models illustrated in Figures 1 and 2. Because the immunologic variables are outcomes that are also nested within the prediction of fluid intelligence, the equation among both women and men that describes fluid intelligence is computed sequentially after the immunology-related equations. The Delta symbol (Δ) is defined as the average level and totality of changes in that variable observed over 6 years. Each coefficient represents the change expected in the outcome if an individual progressed approximately halfway (1.5 standard deviations) along the distribution of that predictor. To offer context for each coefficient, the range of each outcome is listed below the left-hand side of the equation.