Week 4 — Quiz · Economic Growth & Productivity
Course: Principles of Macroeconomics (ECON 2) · Silver Oak University (fictional sample) · Prof. Ashford
Objective 4 · 10 questions · 10 points · closed to AI · one attempt
Auto-graded (Classic QTI): see F-quiz-week-04-qti.xml for the Canvas import. Every numeric answer is pre-computed; this week has no curve-shift claims (Week 4 is growth rates & the rule of 70; curve-shift items resume Week 5).
The questions (human-readable; answer key below)
Q1. An economy's real GDP was 600 (billions) last year and is 630 (billions) this year. What is the economic growth rate?
A) 4.76% B) 5% C) 30% D) 630%
Q2. When computing an economic growth rate as (GDP this period − GDP last period) ÷ X × 100, what does X equal?
A) GDP this period (the new value) B) GDP last period (the old, starting value) C) The average of the two periods D) It does not matter which value is used
Q3. The rule of 70 estimates the number of years for an economy to double as —
A) 70 multiplied by the growth rate B) 70 divided by the growth rate C) The growth rate divided by 70 D) 70 minus the growth rate
Q4. Using the rule of 70, about how many years will it take an economy growing steadily at 3.5% a year to double in size?
A) 245 years B) 3.5 years C) 20 years D) 66.5 years
Q5. A country's total real GDP grows 5% this year. Its population also grows 2% this year. What is the approximate per-capita growth rate?
A) 7% B) 5% C) 3% D) 10%
Q6. An economy has a real GDP LEVEL of $2 trillion this year and grew at a RATE of 4% to get there. Which of these statements correctly distinguishes the level from the growth rate?
A) The level ($2 trillion) answers "how big is the economy right now"; the growth rate (4%) answers "how fast is it getting bigger" B) The level and the growth rate are two names for the same number C) The growth rate tells you the economy's total size, and the level tells you its speed D) Only the growth rate is a real macroeconomic measurement; the level is not meaningful
Q7. (Select all that apply.) Which of the following are among the THREE standard sources of long-run economic growth?
☑ A) Physical capital (factories, machines, infrastructure) ☐ B) The unemployment rate ☑ C) Human capital (education, training, skills, health) ☑ D) Technology (new ideas, processes, innovation) ☐ E) The Consumer Price Index
Q8. (True/False) The rule of 70 gives the EXACT number of years for an economy to double, with no approximation involved. → False
Q9. (Matching) Economic growth rate → (GDP this period minus GDP last period) divided by GDP last period, times 100; The rule of 70 → 70 divided by the growth rate, an estimate of years to double; Per-capita growth rate → Approximately, total GDP growth rate minus population growth rate; The Solow growth model → The standard framework economists use to organize the sources of long-run growth.
Q10. Economy X grows steadily at 2% a year; Economy Y grows steadily at 7% a year, starting from the same GDP. Using the rule of 70, which statement correctly compares their doubling times?
A) Economy X doubles in about 35 years; Economy Y doubles in about 10 years — Economy Y doubles roughly 3.5 times faster B) Both economies double in the same number of years, since the difference between 2% and 7% is small C) Economy X doubles in about 10 years; Economy Y doubles in about 35 years D) Doubling time cannot be estimated without knowing the population growth rate
Answer key & feedback (instructor)
| Q | Type | Answer | Feedback (the idea) |
|---|---|---|---|
| 1 | MC | B | (630−600)÷600×100 = 30÷600×100 = 5% — always divide by the OLD (starting) value; dividing by 630 instead gives the wrong ≈4.76%. |
| 2 | MC | B | The denominator in the growth-rate formula is always GDP LAST period (the starting value) — this is the classic "wrong base" trap, the same one that appears with the inflation rate. |
| 3 | MC | B | Rule of 70 = 70 ÷ growth rate — divide, never multiply. Multiplying gives a wildly wrong, much larger number. |
| 4 | MC | C | 70 ÷ 3.5 = 20 years. (A) is the classic multiply-instead-of-divide error (70 × 3.5 = 245); (D) is 70 − 3.5, also the wrong operation. |
| 5 | MC | C | Per-capita growth ≈ 5% − 2% = 3% — subtract population growth from total GDP growth, don't add or ignore it. |
| 6 | MC | A | The LEVEL answers "how big?"; the growth RATE answers "how fast is it getting bigger?" — the two are never interchangeable. |
| 7 | MA | A, C, D | Physical capital, human capital, and technology are the three standard sources of long-run growth. The unemployment rate (B) and the CPI (E) are Week-3 measurement tools, not sources of growth. |
| 8 | TF | False | The rule of 70 is a close approximation built on compounding math (ln(2) ≈ 0.693, and 70 is chosen because it divides cleanly by common rates) — it is not exact. |
| 9 | Match | as above | Distractor-free direct matches; tests that students can distinguish the growth-rate formula, the rule of 70, per-capita growth, and the Solow model's role from one another. |
| 10 | MC | A | 70 ÷ 2 = 35 years (Economy X); 70 ÷ 7 = 10 years (Economy Y) — Economy Y's higher rate means a MUCH shorter doubling time, not a trivially similar one; (C) reverses which economy gets which doubling time. |
Quantitative gate: PASS — every numeric answer re-computed: Q1 (630−600)÷600×100=5%; Q4 70÷3.5=20; Q5 5−2=3%; Q10 70÷2=35 and 70÷7=10.
Graph-logic check: N/A this week — Week 4 (growth rates & the rule of 70) contains no AD–AS, money-market, or other curve-shift claims; the graph-logic canon resumes with Week 5's AD–AS items.
Quality gate (self-checked): every single-answer item has exactly one correct option; distractors target the named traps (wrong base in the growth-rate formula, multiply-vs-divide on the rule of 70, total vs. per-capita growth, level vs. rate, unemployment-rate/CPI substituted for an actual source of growth). No free numeric entry; no essay.
F-quiz-week-04-qti.xml) ships inside the course's .imscc package — it lands in the Canvas gradebook on import.~ Prof. Ashford's edition · Fall 2026 · built with thecoursemaker.com