The mean of the numbers 15, 21, 17, 26, 18, and 29 is 21. Calculate the standard deviation

  • A 9
  • B 6
  • C 5
  • D 0
waec 2020mathematics

The correct answer is C. 5

x x - \(\overline{x}\))\(^2\) (x - \(\overline{x}\))\(^2\)
15 21 17 26 18 29 -6 0 -4 5 -3 -8 36 0 16 25 9 64
    \(\sum (x - \overline{x})^2\) = 150
Standard deviation = \(\sqrt{\frac{ \sum (x - \overline{x})^2}{n} }\) = \(\frac{150}{6}\) = \(\sqrt{25}\) = 5 Previous question Next question