It is always the same reaction in the same medium at a polymer brush-substrate interface varying properties of the polymer. There is not much of an underlying theory yet that's what i try to develop. I have different sets of experiments varying different properties of the polymer (here i picked one set for illustration) and I want to know if this property has an effect on the reaction rate.

For now i simply cannot produce more data points. If i could measure this quantity directly, I could perform a number of measurements for each condition and perform a t-test to compare two points. This would tell me if the difference between those two is significant or not. I was wondering if there is a similar test for quantities derived from linear regression (as it is the case here).

Ok. Thanks. I had a look into equivalence testing (TOST). The point is, I don't have a defined equivalence boundary. I could arbitrarily pick one, but that's probably not the best choice. Is there sth like a t-test which tells me if the difference between two points is significant or not?

I would like to compare four slopes (which are in fact are reaction rates) I got from linear fits through five data points for each fit. The fitting results for the slopes are as follows:
1: 0.08885 ± 0.00991
2: 0.08744 ± 0.0118
3: 0.10288 ± 0.00669
4: 0.0926 ± 0.01285

My hypothesis is that they are all not significantly different from each other (or in other words that they represent the same reaction rate within an experimental error) and I would like to prove that with a statistical test. But I have no idea which test is appropriate here. If there is somebody with some knowledge on statistics out there, help is very much appreciated. Thanks a lot for your help in advance.