The mean decreases, think about it, if every single value in a data set was decreased by the same number, the average would also go down by the same number
The median would also go down, because the value in the middle of the data set would now be smaller than before
The mode would also decrease, because the value that showed up the most in the data set has now also been decreased
The range, however, stays the same. If the lowest value in a data set was 3 and the highest was 10 and you subtracted 2 from each value in the data set, you would have the lowest at 1 and the highest at 8. But, 10-3 still equals 8-1, so the range is unchanged
