ABSTRACT
This chapter concerns collecting reliable data and then analysing and interpreting them. It presents some simple methods for summarizing data which are given the 'Descriptive Statistics'. They include plotting appropriate graphs and calculating various summary statistics, possibly using a computer package such as MINITAB. Another useful way of plotting data is to construct what is called a cumulative frequency diagram. In addition to the graphical techniques, it is useful to calculate some figures to summarize the data. Any quantity which is calculated from the data is called a statistic. Thus a statistic is a function of the measurements or observations. Most simple statistics can be divided into two types; firstly quantities which are 'typical' of the data and secondly quantities which measure the variability of the data. The former are usually called measures of location and the latter are usually called measures of spread.
