statistical testing

• nominal data

  represented in discrete categories- only be in 1.
• ordinal data

  = doesn't have equal intervals, imprecise and based on subjective opinion.
• interval data

  = based on numerical scales, based on units of equally defined size.
• sign test 


  -looking for a difference

  -use a repeated measure design

  -organise into categories (nominal data)
• how to do a sign test

  1. convert data to nominal data, if the answer is negative we record a negative sign, and if its positive we record a plus sign.
  2. then add up all the pluses and minuses.
  3. we take the less frequent sign and call this S.
  4. now we compare our calculated value with the critical value.
  5. N= number of participants
  6. the calculated value of S must be equal to or less than the critical value for there to be a significant difference.
• Sign test

  = a statistical test used to analyse the difference in scores between related items