Interpreting a Stats Test

• The accepted significance level in psychology is <0.05

  • This means there is less than a 5% probability that the results occurred by chance and more than a 95% probability that the results were due to changing the IV/relationship between co-variables
• The calculated/observed value is a score provided by the appropriate stats test, this is found in the scenario
• The critical value decides whether or not the calculated value is significant
• If the calculated value is significant, we can accept the alternative hypothesis and reject the null hypothesis
• If the calculated value is not significant, we must accept the null hypothesis and reject the alternative hypothesis
• There are 5 statements you use to decide whether the results are significant:

  1. Is it a one tailed or two tailed hypothesis?
  2. The number of participants (degrees of freedom when using chi-squared)
  3. Level of significance (if it doesn't state the p value, assume it is <0.05
  4. Identify the calculated value found in the scenario
  5. Identify the critical value in the table
• The calculated value must be equal to or less than the critical value if any of these stats tests are used:

  • Sign test
  • Mann Whitney U test
  • Wilcoxon test
• The calculated value must be equal to or more than the critical value if any of these stats tests are used:

  • Chi squared test
  • Spearman's Rho test
  • Unrelated t-test
  • Related t-test
  • Pearson's r
• Writing frame:

  The critical value is ___ due to the P value being ___, a ___-tailed hypothesis and where n= ___. The calculated value (___) must be more/less than or equal to the critical value of ___. In this case, the results are significant/not significant, and we reject the ___ hypothesis and accept the ___. So, the is/isn't a significant difference/association between ___.