In order to fill the observed time, let's use the data from the table, and to fill the predicted time, we use the equation of the best fit.
So, for a time t = 11.9, the observed time is 13.00, and the predicted time is:
The residual is the difference between the observed and the predicted values:
Now, for t = 18.1, the observed time is 17.50, and the predicted time is:
The residual is: