Title: Week 14 — the promise, the sample, and the verdict
Course: Introduction to Statistics (18-Week Generic Edition)

Hi everyone,

Last week you learned the courtroom rules: hypotheses, p-values, and the two verdicts. But every p-value was handed to you. This week you compute the evidence yourself — and aim it at the most common claim in the wild: a promised average.

This week — Testing Claims About Means — the big question: a courier promises "50 minutes on average," your 25 timed deliveries average 52 — broken promise, or sampling noise? By the end of the week you'll settle exactly that with the one-sample t-test, handle before/after data with one clever subtraction, and use Week 11's confidence intervals to see what a verdict quietly leaves open.

Three things not to miss: 1. Chapter 14 is your primary reading — the course t-table (the same one from Week 11) is inside, and everything else this week leans on it. 2. Data Lab 14 — "Put the Field Guide on Trial" — your own random sample of penguins tests a reference value. Here's the fun part: the reference is essentially true, so about one classmate in twenty will convict it anyway. Type I error stops being a definition this week; someone in class will commit one, honestly. Due at the end of Week 14. 3. Discussion 14 — "The 'On Average' Alibi" — when a company's claim survives a test, can it advertise "independent testing confirms our claim"? You'll take a side. Initial post two days before the week ends, so classmates have time to reply.

One habit that will carry you through the week: write the standard error on its own line before you touch anything else. Nearly every wrong t this week is a skipped SE.

Open the Start Here / Module Overview page first — it lays out everything in order with due points. Bring a promise you've stopped believing.

See you in the course!