I am new to stats and this is a silly question, but I just cannot see how ANOVA is related to general linear models.
I am learning about GLM and all the materials I found are saying that ANOVA is a kind of general linear model. for example: https://onlinecourses.science.psu.edu/stat504/node/216
I can see how GLM is extended from multiple linear regression, but ANOVA is just the ratio: "variance between" over "variance within". How is it GLM?