Week 3 · Readings & resources

Week 3 — Readings & Resources

Introduction to Statistics Free sample edition

Your primary reading is Chapter 3 (in this module). Everything below is the optional, go-deeper layer — pick what helps, skip the rest.

How to use this page

This page has 12 items (6 readings and 6 videos). Allow 92–107 minutes for everything. Each group points back to the matching chapter section and class-session segment, so use the full menu when you want more practice, or take the quick path below.

Every video here has captions: turn them on with the CC button in the player. The chapter covers the same ideas in text.

Pick-one quick path (20–24 min total)

① Which middle do I report? Mean, median, and mode

Chapter 3, Section “Center: find the middle three ways” · Session 1, Segment 1, “Mean, median, and mode” · Remember: the mode works for labels, the median needs an order, and the mean needs real amounts.

Mean, Median, and Mode: Measures of Central Tendency: Crash Course Statistics #3 — CrashCourse — a lively tour of the three middles, where each one shows up in the news, and how the gap between them hints at the shape of the data. (video, 11 min) (captions: creator)
4.4.2 Calculating the median — Statistics Canada — a national statistics agency's worked examples of the median: sort the values, take the middle one when the count is odd, and average the two middle ones when it is even; the last example reads the median from a frequency table. (reading, 5–8 min)

② Why does one value drag the mean? Resistance and skew

Chapter 3, Section “Skew: let the mean and the median tell you the shape” · Session 1, Segment 3, “Resistance and skew” · Remember: the median holds its ground, and the mean follows the long tail.

Measures of central tendency — Australian Bureau of Statistics — a national statistics office walks through the mean, the median, and the mode, then shows the mean pulled toward the tail in a skewed set of retirement ages and moved by one outlier. This builds on Week 2's work with describing a distribution's shape. (reading, 6–9 min)
Skewness - Right, Left & Symmetric Distribution - Mean, Median, & Mode With Boxplots - Statistics — The Organic Chemistry Tutor — sketches right-skewed, left-skewed, and symmetric shapes and shows where the mean and the median land in each, with a boxplot for every shape. (video, 10 min) (captions: automatic)

③ How spread out are the values? Range, variance, and standard deviation

Chapter 3, Section “Spread: measure how far the values stray” · Session 2, Segment 4, “Range, variance, and standard deviation” · Remember: divide by one less than the count for a sample, and report the standard deviation in the data's own units.

Measures of Spread: Crash Course Statistics #4 — CrashCourse — the range, the interquartile range, the variance, and the standard deviation, each with a reason it exists. Stop here before relationships between two variables; next week takes that up. (video, 12 min) (captions: creator)
Why Dividing By N Underestimates the Variance — StatQuest with Josh Starmer — a patient, picture-driven answer to the question every student asks this week: why a sample divides by one less than its size. (video, 17 min) (captions: automatic)
Measures of spread — Australian Bureau of Statistics — the range, the IQR, and both variance formulas, the population one that divides by the population size and the sample one that divides by one less; skip the sentence about normal distributions, which comes later in the course. (reading, 7–10 min)
Standard Deviation and Variance — Math is Fun — the gentlest page on this list: one small worked example, step by step, then the short section on how the formula changes for sample data. (reading, 5–7 min)

④ What do five numbers tell me? Quartiles, boxplots, and fences

Chapter 3, Section “Five numbers: quartiles, the IQR, and the boxplot” · Session 2, Segment 5, “Five-number summary, boxplots, and fences” · Remember: the box holds the middle half, and the 1.5 × IQR rule flags a value for a closer look, never for automatic deletion.

Central Tendency and Variance (Mean, Median, Mode, IQR, Boxplot) — Physiotutors — a short review from a health-sciences channel that ties the median and the IQR to the boxplot; use it as a quick check before the Week-3 module overview. (video, 7 min) (captions: creator)
Outliers - Box and Whisker Plot (1.5 IQR) — Mario's Math Tutoring — one dataset, its quartiles, its two fences, and the values that fall outside them, worked by hand. (video, 4 min) (captions: automatic)
4.5.2 Visualizing the box and whisker plot — Statistics Canada — how the five numbers become a box and whiskers, including the version that stops the whiskers at 1.5 IQRs and plots flagged values as points; read the first example and skim the comparison of three plots. (reading, 4–6 min)

Optional one-stop reference (free online reference)

7.1.6 What are outliers in the data? — NIST/SEMATECH e-Handbook of Statistical Methods — a federal standards body's reference page on quartiles, the IQR, and the inner and outer fences; read the definitions and the box-plot description, and note that its quartile method can differ slightly from your spreadsheet's. (reading, 4–6 min)

Heads-up (links rot): these point to outside sites that occasionally move or rename pages. If a link ever fails, tell your instructor and use the reference above in the meantime.

Provenance: Built with The Course Maker · samples.thecoursemaker.com