中等MATH-STAT-004
If every value in a data set is multiplied by 3, the standard deviation is
A. multiplied by 3✓ 答案
B. multiplied by 9
C. unchanged
D. increased by 3
解說
A scaling by 3 scales the spread by 3, so the standard deviation is multiplied by 3. The variance, which is the square of the standard deviation, is multiplied by 9.