I am doing a research about glass and conventional cockpits. Research question: " Is there a workload difference between cocpits? I am gonna use 30 pilots in my research. Which one is more sound statistically: 30 pilot flying same pattern on each cockpit then compare these total 60 data or 15 pilot flying same pattern on glass cockpit and 15 pilot flying same pattern on conventional cockpit then compare these total 30 data?