Let's say I have 5 known data points with coordinates
$X$ : Area under curve
$Y$ : Activity
The 5 points have individual error ($\Delta X_{i}$,$\Delta Y_{i}$) on both $X$ and $Y$ and I know that the best fit of these 5 points is a linear fit.
After plotting my 5 original points, I have another one that I only know the Area under curve and not the activity. With the fit equation of my 5 original points, I can associate an Activity to my 6th point. Is there a way to provide a uncertainty to my 6th point ? I have some ideas about Max/Min slopes but I don't know if it's the best way in this situation... And I have to use only Excel at the request of someone.
Thank you !!