From the physical experiment I've got a sample collection of values (unique Y for each unique X). The problem is to find the linear regresstion function of given values collection. Then, assuming that the model is correct, extrapolate found linear function to X=0 and find an appropriate Y value with the confidence interval.
Using MS Excel I've got a graph like this with automatically calculated regression function equation and an R-squared value, which is good. The bad is that I couldn't understand how can I find a confidence interval for Y(X=0) by R-squared value (if it's possible).
The only solution similar to what I need I've found in my coursebook is the way to find the confidence interval for distribution of the constant value measurement (mean of Y), which, I suppose, is not applicable to my problem.
P.S. I can't get more than one value for each unique X because X is actually time. As time rises, the chemical reaction undergoes and electrical conductivity of the solution (which is Y) changes.