Question

Suppose that each number in a data set is decreased by 5. How is the median affected?

1. It is unchanged.

2. It is decreased by 5.

3. You can't tell because it depends on the values in the original data.

Answer 1

the mean is the total divided by the count. So, the original mean is

M = (v1+v2+...+vn)/n

The new mean is

(v1-5 + v2-5 + ... + vn-5)/n
= (v1+v2+...+vn - 5n)/n
= (v1+v2+...+vn)/5 - 5n/n
= M-5

Answer 2

is the answer 2(it decreased by 5)