Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can explain the difference between asking “how big is the difference?” (an interval) and “is there convincing evidence of a difference?” (a test). (Guide: “From an interval to a test”)
- I can explain why the test uses a t-distribution and not the standard normal. (Guide: “Choosing the procedure”)
- I can explain what makes two samples independent, and recognise paired data that need a different test. (Guide: Figure 1 and Worked example 3; Practice Q2)
- I can explain what each of the three conditions protects against. (Guide: “The three conditions”)
Skills
- I can name the two-sample t-test for a difference between two population means in full. (Practice Q2, Q5)
- I can define μ₁ and μ₂ in context, with the response variable, units and each population or treatment. (Guide: “Defining the parameters”; Practice Q5)
- I can write H₀ and a one-sided or two-sided Hₐ in either equivalent form, keeping one order of subtraction. (Guide: Worked examples 1 and 2; Practice Q1)
- I can check the 10% condition for each sample against its own population, and say when it is not needed. (Guide: Worked example 3(d); Practice Q3)
- I can check the sample data condition for small samples with the 1.5 × IQR rule or a graph. (Guide: Worked example 2; Practice Q4, Q6)
Reasoning
- I can decide whether a two-sample t-test is appropriate and explain why not when a condition fails. (Guide: Worked example 3; Practice Q6)
- I can find and correct errors in someone else’s set-up. (Practice Q7)
- I can say, before carrying out a test, whether its conclusion could be about cause and effect and to whom it could apply. (Guide: Worked example 2, Check)
All ticked? Move on to Topic 4.10, Carrying Out a Test for the Difference Between Two Population Means, or return to the course roadmap.