This document discusses the normal distribution curve and how to calculate key metrics like range, cell interval, cell boundaries, variance, standard deviation, mean, median, and mode. It provides the definitions and formulas for calculating each metric and explains how to determine which metric of central tendency (mean, median or mode) is best to use depending on the type of variable (nominal, ordinal, interval/ratio) and whether the data is skewed. The document also discusses how the normal distribution curve has a symmetrical, bell-shaped shape and how the mean, median and mode relate on this curve.