Question

The 25th and the 75th percentiles of a data set are 20 and 36 respectively. Find the coefficient of quartile deviation of the data set.

Answer 1

Here, P₂₅ = 20 ∴ Q₁ = 20 (∵P₂₅ = Q₁)
P₇₅ = 36 ∴ Q₃ = 36 (∵ P₇₅ = Q₃)

Coefficient of quartile deviation:
Coefficient of Q_^d = \(\frac{Q_3−Q_1}{Q_3+Q_1}=\frac{36−20}{36+20}=\frac{16}{56}\) = 0.29