Group B has a higher number of students with lower ages than Group A. Group A also has more older students than Group B. Based on that information Group B would be expected to have a lower mean age.
Group B has a higher number of students with lower ages than Group A. Group A also has more older students than Group B. Based on that information Group B would be expected to have a lower mean age.
Each person shakes 7 hands, but once you count the handshake between A and B, you don't need to count the handshake between B and A. There are a total of 8*7/2 = 28 handshakes.
