Quiz — Lecture 25

Section A from memory, one line each. Section B shows your reasoning - marks are for method, not final answers. Answers are discussed in class; the exit ticket goes on a card.

Section A

A1. Define 'one record' for a class register table.

A2. Rate vs count: what does a rate need?

A3. What is a pivot?

A4. Why print n next to every mean?

Section B

B1. Cohorts A (120, 180, 60) and B (90, 110): means with n, plus one caveat.

B2. A: 40 stayed/10 left; B: 25/25. Churn rates and the denominator sentence.

Exit ticket

Answer one of these on your card in 60 seconds (choose any one):

1. Why state the decision before the computation?

1. Why is the average alone dangerous in cs-098?

1. What made cs-100's survey skew?

Homework

• Before: skim the four student pages; attempt case 1 on paper.
• After: write a five-line pseudocode solution for any case you did not
• Enrichment (optional): the stretch question on each case page.