Mathematics

Problem

Every number in a data set is increased by

7

. Let

\bar{x},\sigma_x

be the original mean and standard deviation, and

\bar{y},\sigma_y

be the new ones. Which statement is always true? a)

\bar{y}=\bar{x}+7

and

\sigma_y=\sigma_x+7

\bar{y}=\bar{x}

and

\sigma_y=\sigma_x

\bar{y}=\bar{x}+7

and

\sigma_y=\sigma_x

\bar{y}=\bar{x}+7

and

\sigma_y=7\sigma_x