Solution:An ANCOVA is similar to an ANCOVA model, but it includes a continuous variable as well as categorical variables as independent variables, being a mixture model of ANOVA and regression models.
An example data is composed of 3 variables, treatment effect, treatment methods (Tx, 2 groups), and age in table 1.
An analysis of covariance procedure is used when the statistical model has both quantitative and qualitative predictors, and is based on the concept of general linear model.