I am testing an automated counting method. To measure its effectiveness I am doing a linear regression model comparing the manual approach to the automatic. This gives me an F statistic for the model adjustment, a coefficient of determination ($R^2$) of the model and the $a$ and $b$ parameters ($y = a + bx$).
Now I would like to determine the minimum sample size to estimate the true counting means within a given error rate of 5%, for example.
Is it possible to be determined?