NUMBAT OER - Open Educational Resources

How to do the test:

  1. State your Null Hypothesis in the form:
    "There is no difference between the populations from which two unrelated samples come"
  2. Choose a Critical Significance Level (α: alpha):
    This is typically α = 0.05.
  3. Calculate the test statistic:
    Use a spreadsheet to calculate your results, or access a helpsheet for SPSS and check here for data entry into SPSS.
  4. Reject or accept your Null Hypothesis.
    Either
    1. Compare the calculated statistic with critical values (Critical values table):
      • If ttcritical → reject H0 → significant result.
      • If t < tcritical → accept H0 → non-significant result.
    2. Look at the calculated probability (P value):
      • If P ≤ α → reject H0 → significant result.
      • If P > α → accept H0 → non-significant result.
  5. Report your results:
    Plot your data using the appropriate graphs.
    (t test: t = …, df = …, P = …)

    View an example report.