Impact on range and mean by increasing salaries

Question

At a particular company, every employee receives a 4% cost-of-living increase to their salary.

What impact does this cost-of-living increase have on the mean and on the range of employee salaries at the company?

Answer 1

There will be 4% increase for mean and range.

For example:
$100    $200    $300    $400 
mean is $250
range is $300

$104    $208    $312    $416 
mean is $260 = $250 + $10
                                     ↑
                                $250*4%
range is $312 = $300 + $12
                                     ↑
                                $300*4%