Descriptive statistics

• The information collected in any study is called data (data set). Numerical data is called quantitive data
• Descriptive data identifies general patterns
• Measures of dispersion are the description of how spread out data is

  1. Range
  2. Standard Deviation
• Range is the arithmetic distance between the top and bottom values in a set of data. You should + 1

  Range is helpful as a further method of describing data

  
• More precise method of expressing dispersion is called standard deviation.
• Nominal data are in two separate categories

  such as grouping people according to their favourite football team.

  Ordinal data are ordered in some way. Use of a scale for example asking people to put a list of football teams in order of liking.
• Interval data is measured using units of equal intervals such as counting correct answers or using public unit of measurements (grading system of A levels and GCSEs)

  Ratio data - same as interval except there is a true zero point