If an experiment had a total of 7 groups, how many pairs of groups could be test with a pairwise comparison?
A)14
B)49
C)7
D)21
E)42

Question

Quizplus · Accepted Answer

The number of pairs of groups that can be tested with a pairwise comparison from a total of 7 groups can be calculated using the combination formula, which is nC2 = n! / [2!(n-2)!], where n is the total number of items (in this case, groups). For 7 groups, it's 7C2 = 7! / [2!(7-2)!] = 21.

If an Experiment Had a Total of 7 Groups, How