computer with keyboard with a number pad
10 sheets of paper containing 5 lines of randomly generated strings of 10 digits
Have a volunteer sit at the computer and place their non-dominant hand over the numberpad.
Next to them place a piece of paper which has 5 lines of 10 digit numbers on it, covered by another piece of paper.
Uncover the paper and start the stopclock. The volunteer should start to input the digits as fast as they can without going back over errors.
Stop the stopclock when they reach the end of the list.
Record the time.
Repeat another 10 times using a different random string set.
Once all the times have been completed go over each data set entered into the computer and count the number of errors input during each trial.
This is a safe experiment to carry out, though if it takes the user a long time to complete the task they may need to be given a short screen break.