DEGREE OF FREEDOM (DF) refers to the number of independent or free-changing data in the sample as the total parameter of the sample, is referred to as the number of independent or freely changed data in the sample is referred to as the degree of freedom of the statistic. For example, when estimating the average of the overall, N number in the sample is added, and any of the numbers are independent, from other data, from which any of them does not affect other data (this is also required for random sampling). ). So each of the data is independent, so the freedom is the number of independent data when estimating the overall parameter, and the average is estimated according to N independent data, so the freedom is n.
In short, it is the number of variables in the model.
