Sign Test

• The sign test is used when looking for a difference between paired data in a repeated measures design, which generates nominal data
• 1. The hypothesis for the sign test can be either directional or non-directional
• 2. Work out the sign by recording each pair of data with a + or - depending on whether the difference is positive or negative. Use 'O' for no difference
• 3. Calculate the value of S by adding up the total number of pluses and minuses and selecting the smaller value
• 4. Calculate the value of N, which is the total number of scores minus any 'O' scores
• 5. Find the critical value using a table and the N value
• 6. Determine the significance of the results by comparing the calculated value to the critical value. Typically, p ≤ 0.05 is used as the probability level
• 7. Report the conclusions of the sign test by stating whether the result is significant or not based on the calculated value compared to the critical value at a significance level of p ≤ 0.05 for a one-tailed or two-tailed test