Find the variance of 11, 12, 13, 14 and 15.

  • A 2
  • B 3
  • C \(\sqrt{2}\)
  • D 13
waec 2016furthermathematics

The correct answer is A. 2

\(Variance (\sigma^{2}) = \frac{\sum (x - \mu)^2}{n}\) The mean \((\mu)\) of the data = \(\frac{11 + 12 + 13 + 14 + 15}{5} = \frac{65}{5} = 13\)
\(x\) \((x - \mu)\) \((x - \mu)^{2}\)
11 -2 4
12 -1 1
13 0 0
14 1 1
15 2 4
Total   10
\(\sigma^{2} = \frac{10}{5} = 2\) Previous question Next question