Factor model for data collected from unrelated individuals. Three factors (F1 to F3) are hypothesized to generate covariance between three endophenotypes (End1 to End3) and four behavioral measurements (Beh4 to Beh7). Causal paths from the factors to the observed variables are drawn as single-direction arrows (e.g., l11, l73). All latent factors (F1 to F3) and residual variance components (RE1 to RB7) are specified to have unit variance. Variation in each observed measurement is thus partitioned into four components: that due to each of the factors and that due to residual variance (including measurement error) specific to each measurement.
