21. Expert and amateur pianists were compared in a study Maintaining Excellence: Deliberate Practice and Elite Performance in Young and Older Pianists

(J. Experiment Psych.: General, 1996: 331—340).

The researchers used a keyboard that allowed measurement of the force applied by a pianist in striking a key. All 48 pianists played Prelude Number 1 from Bach s Well-Tempered Clavier. For 24 amateur pianists the mean force applied was 74.5 with standard deviation 6.29, and for 24 expert pianists the mean force was 81.8 with standard deviation 8.64.
Do expert pianists hit the keys harder? Assuming normally distributed data, state and test the relevant hypotheses, and interpret the results.