Sign test

• What three things do you need to conduct to do a sign test?

  1. You are looking to see whether the difference between two sets of data is significant or not.2. The data gathered is nominal (frequency data - e.g. how many people said yes or no)3. It was a repeated measures or matched pairs design.
• What is nominal data?

  Data that can be placed in categories/groups (colours, Type A/B personality, types of attachment style).
• What is a repeated measures design?


  The same participants are used in both conditions
• What does the observed value need to be to be significant?

  The sign test requires the observed value to be equal to or less than the critical value.
• State if the hypothesis is one tailed or a two tailed test.

  Directional hypothesis - one tailed test.Non-directional - two tailed test.
• How to record the data and work out the sign?

  Put each pair of data in a table and add a + or - depending on the difference between the two scores
• What should you do if the difference is equal in the results table?

  Ignore it and minus the same differences from the N value and use the new number when finding the significance.
• How to find the calculated value (S)?

  To calculate S you add up the number of + and add up the number of - and select the smaller value.
• How to find the critical value of S?

  Find, N = total number of scoresThen work out if its a one tailed or two tailed test
• Is the result significant?

  If the calculated value is equal to or less than the critical value the result is significant.