Читать книгу Analysing Quantitative Data - Raymond A Kent - Страница 16

Cases are the entities under investigation in a particular piece of research. Quantitative data analysis will always relate to a particular set of cases, usually referred to as the ‘sample’ even if that set is not actually a sample but the total number in a population of cases. The set will normally be defined in terms of particular characteristics that define membership and all members will have those characteristics in common. Ideally, the rationale for the selection of such characteristics, for example in terms of their relevance to the inquiry, should always be explained. The number of cases used in any particular analysis will be known and will relate either to the entire set or to some subset. In some research, membership of a research population may be a matter of degree, for example an ‘alcoholic’, a ‘workaholic’, a ‘bulimic’ or an ‘autistic’. Here, the researcher will be constrained to define a particular quantity, for example number of units of alcohol consumed per day or per week, as a cut-off point between inclusion and non-inclusion in the sample of research cases.

In some research projects there may be more than one set of cases, sometimes arranged hierarchically as sets within sets, or sets at different points of time. Sometimes, when a sample is taken, the precise number of cases in the population that the sample is meant to be a sample of is unknown or may or may not be estimated.