# Find Skb for the following set of observations: 18, 27, 10, 25, 31, 13, 28. - Mathematics and Statistics

Sum

Find Skb for the following set of observations:
18, 27, 10, 25, 31, 13, 28.

#### Solution

The given data can be arranged in ascending order as follows:
10, 13, 18, 25, 27, 28, 31.
Here, n = 7

∴ Q1 = value of (("n" + 1)/4)^"th" observation

= value of ((7 + 1)/4)^"th" observation

= value of 2nd observation
∴ Q1 = 13

Q2 = value of 2(("n" + 1)/4)^"th" observation

= value of 2((7 + 1)/4)^"th" observation

= value of (2 × 2)th observation
= value of 4th observation
∴ Q2 = 25

Q3 = value of 3(("n" + 1)/4)^"th" observation

= value of 3((7 + 1)/4)^"th" observation

= value of (3 × 2)th observation
= value of 6th observation
∴ Q3 = 28
Coefficient of skewness,

Sk = ("Q"_3 + "Q"_1 - 2"Q"_2)/("Q"_3 - "Q"_1)

= (28 + 13 - 2(25))/(28 - 13)

= (41 - 50)/15

= - 9/15

∴ Sk = – 0.6

Concept: Measures of Skewness - Bowley’s Coefficient of Skewness
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Chapter 3: Skewness - Miscellaneous Exercise 3 [Page 44]

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