• nominal data – numbers are use as substitute for names or labels and do not have meaning as number – typicaly “enumerated type” in database, in special case “binary data”
  • ordinal data – data has some meaningful order, higher values represent more or different characteristic then lower values, can involve ranks
  • interval data – are ordinal data and equal  intervals between points represent equal changes in quality
  • ratio data – are interval data with so called “natural zero point” – many physical measurements like height etc.
  • continuous / discrete data – continuous can take any value within some rage, dicrete data can only take particular values