Question

The 25th and 75th percentiles of a frequency distribution are 72.18 and 103.99 respectively. Find the quartile deviation.

Answer 1

25th percentile = Q₁ = 72.18.
75th percentile = Q₃ = 103.99 .
Quartile deviation Qd = \(\frac{Q_3−Q_1}{2}\)
= \(\frac{103.99−72.18}{2}\)
= \(\frac{31.81}{2}\) = 15.905 ≈ 15.91