TABLE 12-20 Three New Different Models of Compact SUVs Have Just Arrived

Short Answer

TABLE 12-20
Three new different models of compact SUVs have just arrived at the market. You are interested in comparing the gas mileage performance of all three models to see if they are the same. A partial computer output for twelve compact SUVs of each model is given below:

You are told that the gas mileage population distributions for all three models are not normally distributed.
-Referring to Table 12-20, what are the degrees of freedom of the Kruskal-Wallis test statistic?