which of the following are true about the chi-square goodness of fit test?a. It is common to use one-sided alternative hypotheses when performing the chi-square goodness of fit test
b. The chi-square test statistic follows a Poisson null distribution
c. It compares an observed frequency distribution with an expected frequency distribution
d. The null hypothesis is that there is no difference between the observed and expected values
e. The degrees of freedom are k - 1, where k is the number of classes
f. The nature of the expected frequency distribution depends on the probability model on which it is based