Question

is the quartile deviation for the following data.

12, 5, 7, 3, 1, 13, 17, 5, 19, 13, 1

• A. 16
• B. 8
• C. 10
• D. 5

Answer 1

The correct option is D 5

Arrange the data in ascending order.
1, 1, 3, 5, 5, 7, 12, 13, 13, 17, 19

Here, N = 11
$Q_1$= Size of $\left(\frac{N+1}{4}\right)th$ observation
= size of 3rd observation = 3

$Q_3$= Size of 3$\left(\frac{N+1}{4}\right)th$ observation
= size of 9th observation = 13

Quartile Deviation = $\frac{Q_3-Q_1}{2}$
= $\frac{13-3}{2}$= 5