Question

If the standard deviation of $x_1,x_2,..,x_n$ is $3.5$, then the standard deviation of $-2x_1-3,-2x_2-3$,....., -2x_n-3$ is?

• A. $-7$
• B. $-4$
• C. $7$
• D. $1.75$

Answer 1

The correct option is A $-7$

The Standard Deviation of a set remains unchanged if each data is increased or decreased by a constant however changes similarly when data is multiplied or divided by a constant.

$\therefore$ The SD for the new data set will be $=-2\times 3.5=-7$