If d is the standard deviation x, y, and z, what is the standard deviation of 2x, 2y, 2z ?
If d is the standard deviation x, y, and z, what is the standard deviation of 2x, 2y, 2z ?
Answer/Solution
2d
Steps/Work
If we add or subtract a constant to each term in a set:
Mean will increase or decrease by the same constant.
SD will not change.
If we increase or decrease each term in a set by the same percent (multiply by a constant):
Mean will increase or decrease by the same percent.
SD will increase or decrease by the same percent.
So in our case SD will change by same multiple (% increase) as we are multiplying each number in a set by 2--> SD=2d.
Answer: B.
Mean will increase or decrease by the same constant.
SD will not change.
If we increase or decrease each term in a set by the same percent (multiply by a constant):
Mean will increase or decrease by the same percent.
SD will increase or decrease by the same percent.
So in our case SD will change by same multiple (% increase) as we are multiplying each number in a set by 2--> SD=2d.
Answer: B.