[PR #1632] fix(labs): correct debt multiplier answer in lab 14 Part D #9238

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GiteaMirror · 2026-05-03T01:29:48-05:00

GiteaMirror commented

2026-05-03 01:29:48 -05:00

📋 Pull Request Information

Original PR: https://github.com/harvard-edge/cs249r_book/pull/1632
Author: @Shashank-Tripathi-07
Created: 5/3/2026
Status: 🔄 Open

Base: dev ← Head: fix/lab14-debt-multiplier-answer

📝 Commits (1)

a15b0a2 fix(labs): correct debt multiplier answer in lab 14 Part D

📊 Changes

1 file changed (+4 additions, -4 deletions)

View changed files

📝 labs/vol1/lab_14_ml_ops.py (+4 -4)

📄 Description

Summary

Part D asks: "You defer retraining for 3 consecutive T* cycles. Total accuracy loss vs single miss?"

The answer key marked "C) ~5-6x (debt compounds)" as correct, but the debt cascade formula with default sliders (N=3 missed cycles, 2 downstream models, 2 pp/cycle, alpha=1.3) computes:

compound loss = sum(2 * k^1.3, k=1..3)  = 2*(1 + 2.46 + 4.73) = 16.4 pp
cascade cost  = 3 * 2 * 2.0 * 0.3       =                        3.6 pp
total                                    =                       20.0 pp
multiplier    = 20.0 / 2.0              =                        ~10x

The dynamic display card already showed ~10x while the answer marked ~5-6x as correct -- a visible contradiction.

Changes

All four places that stated the wrong "5-6x" figure are corrected to "~10x":

Learning objective text
Radio option C label: "~5-6x (debt compounds)" → "~10x (debt compounds)"
Answer key value: "5x" → "10x"
Synthesis summary callout

Test plan

Open lab 14 Part D with default sliders (3 cycles, 2 downstream, 2 pp/cycle)
Confirm debt multiplier card shows ~10x
Select "C) ~10x (debt compounds)" -- confirm "Correct" callout appears

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/harvard-edge/cs249r_book/pull/1632 **Author:** [@Shashank-Tripathi-07](https://github.com/Shashank-Tripathi-07) **Created:** 5/3/2026 **Status:** 🔄 Open **Base:** `dev` ← **Head:** `fix/lab14-debt-multiplier-answer` --- ### 📝 Commits (1) - [`a15b0a2`](https://github.com/harvard-edge/cs249r_book/commit/a15b0a2401d2bcd94d2025489615eab2b8403bbc) fix(labs): correct debt multiplier answer in lab 14 Part D ### 📊 Changes **1 file changed** (+4 additions, -4 deletions) <details> <summary>View changed files</summary> 📝 `labs/vol1/lab_14_ml_ops.py` (+4 -4) </details> ### 📄 Description ## Summary Part D asks: "You defer retraining for 3 consecutive T* cycles. Total accuracy loss vs single miss?" The answer key marked **"C) ~5-6x (debt compounds)"** as correct, but the debt cascade formula with default sliders (N=3 missed cycles, 2 downstream models, 2 pp/cycle, alpha=1.3) computes: ``` compound loss = sum(2 * k^1.3, k=1..3) = 2*(1 + 2.46 + 4.73) = 16.4 pp cascade cost = 3 * 2 * 2.0 * 0.3 = 3.6 pp total = 20.0 pp multiplier = 20.0 / 2.0 = ~10x ``` The dynamic display card already showed `~10x` while the answer marked `~5-6x` as correct -- a visible contradiction. ## Changes All four places that stated the wrong "5-6x" figure are corrected to "~10x": - Learning objective text - Radio option C label: `"~5-6x (debt compounds)"` → `"~10x (debt compounds)"` - Answer key value: `"5x"` → `"10x"` - Synthesis summary callout ## Test plan - [ ] Open lab 14 Part D with default sliders (3 cycles, 2 downstream, 2 pp/cycle) - [ ] Confirm debt multiplier card shows ~10x - [ ] Select "C) ~10x (debt compounds)" -- confirm "Correct" callout appears --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

GiteaMirror added the pull-request label 2026-05-03 01:29:48 -05:00

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Reference: github-starred/cs249r_book#9238