The first unit took 10 hours and the fourth unit 8.1 hours. What is the improvement rate?
A) 99%
B) 95%
C) 90%
D) 15%
E) none of the above

Question

Quizplus · Accepted Answer

The improvement rate can be calculated using the formula for learning curve or improvement rate: $IR = \left(\frac{T_n}{T_1}\right)^{\frac{1}{n-1}}$, where $T_n$ is the time taken for the nth unit, $T_1$ is the time taken for the first unit, and $n$ is the unit number. For the fourth unit ($n=4$), $T_1=10$ hours and $T_4=8.1$ hours, the formula becomes $IR = \left(\frac{8.1}{10}\right)^{\frac{1}{4-1}}$, which simplifies to $IR = \left(0.81\right)^{\frac{1}{3}}$. This does not match any of the provided options exactly, indicating the correct answer is E, none of the above.

The First Unit Took 10 Hours and the Fourth Unit