A different chi-square distribution exists for each possible number of degrees of freedom because the ramdom varible is a sum of sqauares , negatuvevalues are impossible ;all values therefore range between zero and positive infinity. Even though all chi-sqaue distributions are,thus,skewed to the right, the extent of skewness decreases with incresing numbers of degrees of freedom. chi-square distribution with 30 degrees of freedom or more very closely approach the normal distribution, a fact that is already evident by comparing panels through