Roadmap
Day 33 · Spread 47 min 40 XP
📏Variance, standard deviation and z-scores
Two groups can share the same average and still be nothing alike. Standard deviation measures the spread, and a z-score turns any value into 'how many spreads from normal'.
What you'll learn
- Calculate variance and standard deviation by hand and in Sheets
- Choose between STDEV.S and STDEV.P
- Compute and read a z-score
A peek inside
Variance and standard deviation
The rest of Day 33 is a Pro lesson
You're on the free Explorer plan — you get the intro and the video. Go Pro to open the full guided lesson (and all 30 days).
- 3 deep-dive lessons
- A copy-paste worked example
- 3 hands-on practice tasks
- Studio task: Spread and z-scores by hand and by formula
- 3-question quiz, up to 45 XP
- 4 quick-glance glossary cards
- 40 XP + streak tracking
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