Find the inter-quartile range of 1, 3, 4, 5, 8, 9, 10, 11, 12, 14, 16
A
6
B
7
C
8
D
9
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
\(Q_1 = \frac{1}{4}\) (N + 1)th
\(\frac{1}{4} \times 12^{th}\) no.
= 3rd no (\(\cong\) 4)
\(Q_3 = \frac{3}{4}\) (N + 1)th
= \(\frac{3}{4}\) x 12th no.
= 9th no. (\(\cong\) 12)
Hence, interquartile range
= \(Q_3 - Q_1\)
= 12 - 4
= 8
Source: Myschool Past Questions Archive (Record #49403)