Calculating least squares for OHLC chart

This maybe a dumb question but im trying to calculate the least squares line for a OHLC chart and not sure how calculate for the entire range of each OHLC bar. I know how to calculate least squares when it just the closing price but how do you calculate it when incorporating the entire range of each bar? Do you calculate the least squares for each variable(open,high, low, close) and then take an average?

 

Thats how I would do it ..

 

i was also thinking doing a least squares of the median of each bar on the chart but im not sure if thats correct either

 

Sounds like a better route than your origional post.