Students (# = 5)

Adults (# = 5)

Group A + B

Mean hit rate (# of answered pairs/40 × 5)

0.705 (141/200)

0.780 (156/200)

(2834 words)

Estimated density $p_{A+B}$

0.1149

0.1405

[# of each type in answered pairs]

AA = 30, AB = 67, BB = 44

AA = 32, AB = 66, BB = 58

Group B

Mean hit rate (# of answered pairs/40 × 5)

0.550 (110/200)

0.800 (160/200)

(1744 words)

Estimated density $p_{BB}$

0.0767

0.1487