ABSTRACT
This chapter explores graphs and charts in terms of how they are constructed and what they represent. Both graphs and charts ultimately represent and are constructed using what are called frequency distributions: predetermined organizational categories that group and summarize observations of a given variable(s). Quantitative versus qualitative variables, however, call for different types of histograms, frequency polygons, bar charts, and pie charts. The chapter discusses quantitative and qualitative frequency distributions in terms of what they represent and how they are constructed. At the most basic level, frequency distributions take raw data, also referred to as ungrouped data, and group (place) them into predetermined categories. When dealing with quantitative variables (ordinal and interval-ratio levels of measurement), the grouping of data is accomplished using numerical categories representing a range of numbers. A quantitative frequency distribution, then, is made up of predetermined numerical categories that are mutually exclusive and exhaustive.
