By common definition, a “statistic” is the description of a population through numbers, usually based on a specific group. In technical language, however, the study of said numbers in a population as a whole is referred to as a “parameter”.  Different types of statistics exist: graphs, frequency distributions, central tendency and variation estimation, and reliability tests are all common examples. The statistic needed hinges on whether single variables or multi-item scales are to be evaluated. In order to improve accuracy and reliability, other statistics can be used to illustrate association and control within variables.  An appropriate demonstration of the above is cross-tabulation, as per mentioned in this chapter. It is a means of measuring factors that are in symbiosis with other variables.  These are all different cases of descriptive statistics; the data provided describes the variables in accordance to their distribution and relationship. Inferential statistics are also used in order to estimate the reliability of generalizations that can be made of population, based on the selected sample.