N3-01 Definition: Front—How is the arithmetic mean calculated? Back—Sum all observations and divide by their count; extreme values can strongly affect it. Source N3 2.1. Likely error: divide by range. Cue: denominator is number of observations.
N3-02 Procedure: Front—Find the median of 8, 2, 5, 3. Back—Order 2,3,5,8; even count, so average the middle two: (3+5)/2=4. Source N3 2.2. Prerequisite ordering. Likely error 5; cue “order first, then locate middle.” N3-03 Calculation: 2,3,3,4,40 → mean 10.4, median 3, with visible sums; source 2.3. N3-04 Discrimination: a few extremes make mean misleading for “typical”; median may be preferable, but not always and it does not explain skew; source 3.1. N3-05 Non-example: symmetric data with one suspected data-entry error—do not automatically choose median; first verify the record. The verification step is an application cue, not stated in N3, so mark Source gap and exclude unless instructor approves. N3-06 Definition: IQR=Q3-Q1, middle 50%; source 4.1. N3-07 Ambiguity: course uses exclusive quartiles; software may differ—state convention before comparing; source 4.1.
Schedule, adjustable: day 1 cards 01-03; day 2 recall 01-03 then add 04/06; day 3 add 07 plus mixed calculations; day 4 review failures; day 5 none; days 6, 8, 10, 12 review due cards, with a scenario set on days 8/12. Fifteen-minute cap: 2 min free recall, 10 min due cards, 3 min error rewrite. Rate Again if target was absent/wrong, Hard if correct only after a cue, Good if correct with reasoning, Easy only if immediate and complete. After two lapses, rewrite/split; suspend cards with disputed source. Coverage: all five goals covered; N3-05 excluded pending approval.