Question

If 25% of the item are less than 20 and 25% are more than 40, the quartile deviation is

• A. 20
• B. 30
• C. 40
• D. 10

Answer 1

Answer: (D)

10

Answer 2

Here, we are given that the lower quartile $Q_{1} = 20$ and the upper quartile $Q_{3} = 40$

Hence quartile deviation $\frac{Q_{3} - Q_{1}}{2} = \frac{40 - 20}{2} = \frac{20}{2} = 10$.