Strain%=0.1077+0.0454t, and r²=0.9990 (coefficient of determination).
When t=12.45min, strain%=0.6727 approx.
My calculator has a few basic statistical functions built in, so, since the calculations are tedious and time-consuming, as well as taking up space and because of editing difficulties I experience, I present only the linear regression equation, coefficient of determination and a calculated strain percent.
