Frequency Distributions

Consider a numerical variable x (continuous or discrete) with values in [a, b] and let \(\mathcal {P}\) be a partition of [a, b] into K monotonically increasing intervals (bins). The frequency distribution (histogram) of x over \(\mathcal {P}\) is a function that returns the number of values of x that fall within each bin. Visualizing the distribution of all the observations in a quantitative dataset is essential to gain a better understanding of its shape, center, and spread. This chapter presents different approaches for visualizing frequency distributions: histogram plots, dot diagrams, pyramid plots, and area charts.