Constant Variance (Homoscedasticity)

This selection assumes the random errors in the regression model are homoscedastic (have constant variance) and estimates the regression coefficients by ordinary least squares for both model ln (y) = xb and model y = xb.

Note: This option is automatically selected if your input data file contains only 2 fields.

Adding 0.5 to Zero Counts

When analyzing counts or computing crude rates, Joinpoint will add 0.5 to any zero count under the circumstances listed here.