This chapter presents an introduction to the key elements of descriptive statistics: the ways in which quantitative information can be presented and described. The first step in the analysis of quantitative data is its organization and presentation in tables and graphs. The basic features of the data – such as its central or most common values and the way the observations are distributed around these central values – can then be summarized in various ways.

Presentation of numerical data

Frequency distributions

Quantitative data in their raw form consist of a series of numbers or categories. For example, the Poor Law data on per capita relief expenditure in 1831 by the 24 parishes in Kent could be set out in its original sequence as in table 2.1, with the data rounded to one decimal place.

Even with 24 observations it is difficult to get much sense of the data in this form. It would help a little if the values were arranged in ascending or descending order of magnitude (known as an array). This would immediately show the highest and lowest values and give some indication of the most common level of payment, but with a large number of observations it would still be hard to interpret the information in this form.