Question

For numbers 10, 20, 30, 40, 50, 60, 70 and 80; the inter-quartile range is ______.

Options

• 20 + 60

• 60 - 30

• 60 - 20

• 50 - 10

Answer 1

For numbers 10, 20, 30, 40, 50, 60, 70 and 80; the inter-quartile range is 60 - 20.

Explanation:

Numbers in ascending order : 10, 20, 30, 40, 50, 60, 70 and 80.

The number of terms (n) are 8, which is even.

∴ Lower quartile = `n/4 = 8/4`​​ = 2^nd term = 20

∴ Upper quartile = `(3n)/4 = (3 × 8)/4 = 3 × 2` = 6^th term = 60

Inter-quartile = Upper quartile - Lower quartile = 60 - 20