sign test

• Sign test


  A statistical test that can only be used for a study that looked for a difference not an association, used a related experimental design, and collected nominal data
• How to conduct a sign test

  1. State the hypotheses

  2. Record data and work out the sign

  3. Find the calculated value for the sign test, S, which is the number of times the less frequent sign occurs

  4. Find the critical value of S
• An example of a statistical test is the sign test
• Sign test

  • Can only be used for a study that:
  • Looked for a difference not an association
  • Used a related experimental design- repeated measures design
  • Collected nominal data
• How to conduct a sign test

  Step 1 - State the hypotheses- this includes both the alternative and the null hypothesis

  Step 2 - Record data and work out the sign. For example, the sign will be negative (-) if the value has decreased in the second condition but positive (+) if it has increased. If the value has stayed the same , this value will be ignored and the N adjusted to exclude it

  Step 3- Find the calculated value for the sign test, S, which is the number of times the less frequent sign occurs

  Step 4 - Find the critical value of S - use the calculated N value (which is the total number of values with the ignored values excluded) and p≤ 0.05 which means there's a less than 5% probability that the results occurred by chance

  If S ≤ critical value- reject the null hypothesis, there is a significant difference

  If S ≥ critical value - accept the null hypothesis, there is no significant difference

  Step 5 - State conclusion whereby you refer back to the hypothesis mentioning the IV and DV and support your conclusion with the exact values of the critical value, S, N and what p value you used