Week 12 — Readings & Resources
Your primary reading is Chapter 12 (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 10 items (4 readings and 6 videos). Allow 56–69 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 (18–22 min total)
- Confidence Interval for a population proportion | Solved Problems — Joshua Emmanuel
- Margin of Error: Formula and Interpreting — Statistics By Jim
- Methods 101: Question Wording — Pew Research Center
① Building the interval for a share
Chapter 12, Section “The one-proportion z interval: build it by hand and by spreadsheet” · Session 1, Segment 2, “Building the one-proportion z interval” · Remember: the interval is the sample proportion plus or minus the critical value times its standard error, after checking for at least 10 successes and 10 failures.
- An Introduction to Inference for a Proportion — jbstatistics — a careful, notation-exact walk through the standard error of a sample proportion, the large-counts check, and the interval formula. This builds on Week 11's work with confidence intervals for a mean. The second half moves on to a test for a proportion: stop here before the hypothesis-test half; next week takes that up. (video, 10 min) (captions: automatic)
- Confidence Interval for a population proportion | Solved Problems — Joshua Emmanuel — a chaptered worked problem from the point estimate through the standard error, the critical value, the two ends, and the interpretation, with a look at how the confidence level and the sample size change the width. (video, 7 min) (captions: creator)
- Confidence Interval for a Population Proportion - Google Sheets — Matthew Simmons — a short spreadsheet build of the same interval in Google Sheets, the tool the Data Lab uses; follow along while completing the Week-12 module overview. (video, 3 min) (captions: creator)
② Reading a poll's margin and planning a sample size
Chapter 12, Section “Read a poll's margin of error” · Session 2, Segment 3, “Poll margins and choosing a sample size” · Remember: a poll's margin is reported in percentage points, and four times the people halves it.
- How precise are polls...really? — Pew Research Center — a two-minute plain-language look at what a poll's margin of error means and why a poll of about a thousand people can still be useful. (video, 2 min) (captions: creator)
- Margin of Error: Formula and Interpreting — Statistics By Jim — read the parts on the maximum margin of error for a survey, the formula with a share of 0.5, and the caveats at the end; the maximum margin for 1,000 people matches the course's poll ladder. (reading, 6–10 min)
- Confidence Intervals for a Proportion: Determining the Minimum Sample Size — jbstatistics — solves the margin formula for the sample size, including the case with no earlier estimate, and shows why the result is rounded up to a whole person. (video, 11 min) (captions: automatic)
- The margin of error: 7 tips for journalists covering polls and surveys — The Journalist's Resource — read tips 1, 2, 6, and 7 on margins in percentage points, larger samples, smaller subgroups, and differences between polls. Watch for places where "3%" really means 3 percentage points. (reading, 4–7 min)
③ What the margin of error leaves out
Chapter 12, Section “What the margin of error does not cover” · Session 2, Segment 4, “What the margin of error leaves out” · Remember: the margin of error measures random sampling wobble only; who was asked, who answered, and how the question was worded sit outside it.
- Methods 101: Question Wording — Pew Research Center — short, concrete examples of how the wording and order of a question shift the answers, an error no margin of error reports. (video, 5 min) (captions: creator)
- Building Trust Through More Realistic Expectations… And a More Accurate Margin of Error — AAPOR — a short piece from the professional association of survey researchers arguing that the usual margin covers sampling error only and leaves out coverage, non-response, and measurement error. (reading, 3–5 min)
Optional one-stop reference (free online reference)
- Uncertainty and how we measure it for our surveys — Office for National Statistics — a free government reference from the United Kingdom's national statistics office; read Section 2 on sampling and non-sampling error and Section 5 on confidence intervals, and skip the rest of the page. (reading, 5–9 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