When data is collected from an experiment or a survey, or generated as the result of numerical work on a computer, it is often very extensive. We therefore need to consider ways in which to summarise a large amount of data into more manageable and easily understood forms. This summary can be in the form of a table such as a frequency distribution, a picture such as a histogram or numerical values such as the mean and standard deviation. These things are designed to give a summary of the data so that we can visualise its shape and location, which we cannot often do from the raw values.
Unable to display preview. Download preview PDF.