Question: what is the formula of coefficient of quartile deviation?
Answer: Formally, the Quartile Deviation is equal to the half of the Inter-Quartile Range and thus we can write it as – Q d = Q 3 – Q 1 2 Q_d = \frac{Q_3 – Q_1}{2} Qd=2Q3–Q1 Therefore, we also call it the Semi Inter-Quartile Range. The Quartile Deviation doesn't take into account the extreme points of the distribution.