So I made a graph in R, it’s a linear regression of the same sample at different concentrations. It has a confidence interval built into it of 95%. Then I had to determine the concentration of an unknown sample. I got about 5 samples and got their average and made an error bar with 2 Standard Errors. Would this be enough to show that the unknown concentration can be explained and determined by the linear regression? Also, what T-test should I do to further show that the concentration is explained by the linear regression.