Figure 2.

Best fitting structural equation model of associations among paternal occupation, overcrowding, IQ at age 11, and age at death up to 76 years. All parameter estimates are significantly greater than zero. Squaring the parameter weights gives the variance shared by adjacent variables; they are comparable to partial β weights in linear regression. Average off diagonal standardised residuals=0.013; χ² (df=2)=3.29, P1=0.19; Bentler Bonett normed fit index=0.965, Bentler Bonett non-normed fit index=0.956; comparative fit index=0.985. All of these indices are indicative of a well fitting model