Q.In a town, 25% of the persons earned more than ₹45,000 whereas 75% earned more than ₹18,000. Calculate the absolute and relative values of dispersion.

The two percentages identify the upper and lower quartiles, from which the quartile deviation and its coefficient follow directly. …

Step 1 — Identify the quartiles. If 25% earned more than ₹45,000, then 75% earned less, so ₹45,000 is the value below which three-quarters of the persons fall — the third quartile: $Q_3 = 45{,}000$. If 75% earned more than ₹18,000, then 25% earned less, so ₹18,000 is the value below which one-quarter fall — the first quartile: $Q_1 = 18{,}000$.

Step 2 — Absolute measure (quartile deviation). …