Linear interpolation?

Question

Mathematics

Good afternoon! There is such an interesting problem, there is a calculated graph of some process P (say, a semi-hyperbola), there is a graph of the real process Pr (it turns out, approximately, the same semi-hyperbola, but with slight deviations in the sections). The calculation chart has some allowable range of delta value change (+-1). Some kind of tricky interpolation device is needed so that the resulting line averages both graphs and passes as much as possible in the allowable range (of course, there may be small out of range). Picture:

Answer 1

so that the resulting line averages both graphs

(P + Pr) / 2

Answer 2

Standard deviation.