Title: Welcome to Week 3 — the week the average goes on trial
Course: Introduction to Statistics (18-Week Generic Edition)

Hi everyone,

Nice work last week — you turned raw numbers into histograms and learned to read a distribution's shape, including the graphs designed to fool you. Keep that skepticism handy, because this week's target is even more common than a bad graph: the "average."

This week — Numerical Summaries: Center & Spread — we tackle the big question: Can one number honestly stand in for a hundred numbers — and which number should it be? You'll learn all three centers (mean, median, mode), the spread measures that give a center its meaning (standard deviation, IQR), a formal rule for flagging outliers, and the z-score — the trick that lets you compare a commute time to a grocery bill.

Three things not to miss: 1. Chapter 3 is your primary reading — start there. The moment a single crash-day commute drags a mean from 20 to 32 minutes while the median doesn't budge is the whole week in one example. 2. Data Lab 3 hands you the penguins again — this time you'll summarize each species' body mass and then sabotage your own data with a 9,999-gram typo to watch, live, which summaries survive. Due at the end of Week 3. 3. The Discussion ("The Average That Misled Me") wants your initial post two days before the week ends — pick a real average from your life and put it on trial.

One heads-up: this is the first real computation week, and your chatbot will get some of it wrong — there's a divide-by-the-wrong-number error most of them make on standard deviations. Catching it is literally part of this week's work. The tool drafts; you judge.

Open the Start Here / Module Overview page first — it lays out everything in order with due points. Bring a healthy distrust of the word "average."

See you in the course!