Question

If the SD . of a set of observations is 8 and if each observations is divided by -2, the S.D. of the new set of observations will be

• A. -4
• B. -8
• C. 4

Answer 1

The correct option is C

4

If a set of observations , with SD $\sigma$ , are multiplied with a non-zero real number, a, then SD of the new observations will be $|\alpha |\sigma$.

Dividing the set of observations by -2 is same as multipliying the observations by $\frac{1}{-2}$.

New S.D =$|-\frac{1}{2}|\times 8=\frac{8}{2}=4$