ABSTRACT
This chapter focuses on statistics that summarizes the distribution of scores on variable. All measures of central tendency and dispersion are based on a summary of values and cases termed a frequency distribution. A frequency distribution is simply an ordered count of the number of cases that take on each value of a variable. The measure of central tendency for interval/ratio data is the mean a measure that locates the central point of a distribution in terms of both the number of cases on either side of that point and their distance from it. The mean of a distribution is the statistic many people commonly associate with the term average. Interval/ratio values can be subjected to any arithmetic manipulation. Consequently, the measures of central tendency and dispersion for interval/ratio data can and should take the added information and capability into account.
