posted by mysterychicken .
No clue how to solve this.
If you have performed a linear regression of data that ranges from 1-10 and has a y=2x+5, what is the extrapolated value for y at 11
this is easier than you are trying to envision it. You have a bunch of data, and you have found that the straight line of best fit is
y = 2x+5
You have no real formula that produces every data point in the interval [1,10], but this line does as well as you can.
So, now you have a line which closely fits all observed data. To extrapolate to other data, all you can do is estimate based on your calculations so far.
y(11) = 27