bo
bo is a sample estimate of a population parameter ß0. In a model that only contains a single parameter, b0 is the sample mean. In a model with multiple estimated parameters, b0 is the constant in the regression equation. It estimates ß0 (the population mean in a single parameter model, or the population constant in a multiple parameter regression model). Please read pages 72 and 73 in Judd and McClelland, and refer to the descriptions of ß0, B0, and ßj.