Given that the mean of the scores 15, 21, 17, 26, 18 and 29 is 21, calculate the standard deviation of the scores
-
A.
(sqrt{10}) -
B.
4 -
C.
5 -
D.
(sqrt{30})
Correct Answer: Option C
Explanation
(begin{array}{c|c} x & x – x & (x – bar{x})^2\ hline 15 & -6 & 36\21 & 0 & 0\17 & -4 & 16\ 26 & 5 & 25 \ 18 & -3 &9 \ 29 & 8 & 64 end{array})
(E(x – bar{x})^2) = 150
N = 6
S.D = (sqrt{frac{(x – x)^2}{N}})
S.D = (sqrt{frac{150}{6}}) = 5