If d is the mean of x, y, and z, what is the mean of x + 5, y + 5, z + 5 ?
Choose the correct answer:
A) d
B) 3d
C) 15d
D) d + 5
E) d + 15
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 mean will increase by 5 as we are adding 5 to each term in a set --&gt; Mean =d + 5.   Answer: d + 5.
<result>D</result>
If d is the mean of x, y, and z, what is the mean of x + 5, y + 5, z + 5 ?