Week 14 — Tests for Means & Proportions
Welcome to your Week 14 Start Here page.
Why this matters
A hospital quality team checking whether waits got shorter and a field biologist comparing two penguin species both need to know if a gap is real or only sample wobble.
In plain language
Last week you learned how a hypothesis test (a way to weigh data against a claim by asking how surprising the data would be if the claim were true) works on a guessing quiz. This week you run the same logic on the questions people ask most often: whether an average differs from a claimed value or from another group's average, and whether a share differs from a claimed share or from another group's share. You will learn four tests, one for each of those questions, and how to read them from a spreadsheet or from software. You will also see that a test and a confidence interval (a range of believable values for a population's true value) are two views of the same question. Choosing the right test, and saying honestly what its answer means, is the main skill of the week.
- Already covered: Weeks 11 to 13 built confidence intervals and the logic of a test.
- This week: four tests for means and proportions.
- How they connect: each test counts standard errors from a claim.
- Where we're going next: Week 15 tests a regression slope.
Focus
Is a gap in means or shares real, and how big could it be?
By the end of this module, you should be able to:
- [ ] run one-sample and two-sample t tests
- [ ] run one- and two-proportion z tests
- [ ] say why "not significant" is not "no difference"
- [ ] choose the right test
To-do
Plan your week
- Read Chapter 14 (about 50 minutes), then the lecture and slides.
- Do the tutorial (60–90 minutes) and practice (20 minutes).
- Do the Data Lab (90 minutes), the discussion, and the assignment.
- Take the quiz.
This week's checkpoint: test the penguin sex split and state the result without saying "no difference".
Built with The Course Maker · samples.thecoursemaker.com