ABSTRACT
This chapter explains concepts that are both abstract and concrete at the same time. The normal distribution, chi-square distribution, probabilities, and how they relate to each other are abstract to many individuals, especially since they are constructs that we do not think about in our everyday lives. Chi-square probability distribution is based on a series of distributions that pertain to categorical data. It is dependent on the number of categories or groups within the categorical variable. Significance testing is based on the probability that there is no difference or meaningful result. The probability is that of random chance. A categorical variable has dichotomous, nominal, or ordinal data. The observations are the result of a counting process. Therefore, categorical data consist of counts or frequencies and the proportions or percentages of those counts in relation to the total sample size or to subgroups within the variable.
