The data given below shows the rainfall (in cm) recorded in a city on 5 different days.
Rainfall: 5, 6, 8, 10, 11
Find the sample variance of the given data.
Show answer & explanation
Correct answer: C
Explanation
5, 6, 8, 10, 11
Mean = (5 + 6 + 8 + 10 + 11) ÷ 5
= 40 ÷ 5 = 8
Calculating (x − 8)² -
(5 − 8)² = 9
(6 − 8)² = 4
(8 − 8)² = 0
(10 − 8)² = 4
(11 − 8)² = 9
Sum = 26
Variance -
= Σ(x − x̄)² ÷ (n − 1)
= 26 ÷ (5 − 1)
= 26 ÷ 4 = 6.5