Back transforming square root transformed data


New Member
Can anyone help me understand how to go about back transforming this data to absolutes. The Y axis is the square root transformed Return on Assets managed which is a financial measure of business operating performance (Profit EBIT divided by total asset value). THe X axis is time running from 2004 to 2017. I am only after the Median by year for the blue and the red boxes. I have been told that this can be back transformed by multiplying each median number by itself but the output looks lower than I would expect with very little volatility (relative to what I would expect).