Question

Find the coefficient of quartile deviation for the observations:

8, 15, 2, 11, 20, 3, 5

Answer 1

Writing observallons In ascending order
2. 3. 5. 8. 11, 15. 20
Here. n = 7
First quartile:
Q₁ = Value of (\(\frac{n+1}{4}\))th observation
= Value of (\(\frac{7+1}{4}\))
= 2nd observatIon
= 3

Third quartile:
Q₃ = Value of 3(\(\frac{n+1}{4}\)) th observation
= Value of 3 (2) = 6th observatIon
= 15

Coefficient of quartile deviation:
Coefficient of Q_d = \(\frac{Q_3−Q_1}{Q_3+Q_1}=\frac{15−3}{15+3}\)
= \(\frac{12}{18}=\frac{2}{3}\) = 0.67