descriptive statistics

• descriptive statistics

  - once quantitative data has been collected, it must numerically summarised

  allows researchers to view the data as a whole

  -include a measure of central tendency and dispersion and can also include percentages
• measures of central tendency

  • tell us about the central, most typical value in a data set and are calculated in different ways
  • measures of central tendency are the mean, median and mode
• measure of dispersion

  • descriptive statistics that define the spread of data around a central value (mean or median)
  • the 2 measures of dispersion are range and standard deviation
• large standard deviation

  -data is widely spread around the mean with no consistency
• small standard deviation

  • narrow spread of scores around the mean with consistent similar scores
• standard deviation

  • looks at how far the scored deviate from the mean
• zero standard deviation

  • all of the data (scores) wass the same
• evaluate the range

  +easy to calculate without a calculator

  -doesn't indicate the distribution pattern across the whole data set
• evaluating standard deviation

  +precise measurement as it incudes all values in the data set

  -extreme values can distort the measurement