"This handbook describes statistical techniques to turn data into information for answering these types of questions and many others. The techniques range from simple to complex. For example, the next two chapters describe how to develop charts to provide more effective presentations about fire problems. These charts may be beneficial to city or county officials on the activities and needs of your fire department. Chapter 4 discusses measures of central tendency (means, medians, modes) and measures of dispersion (range, variance, standard deviation). In Chapter 5, the chi-square statistic and its use in analyzing table data is presented. In Chapter 6 the Pearson correlation coefficient and some additional correlations are discussed. These are all techniques that can tell you more about the nature of fires and injuries."
U.S. Fire Administration: http://www.usfa.dhs.gov/