Consider a collection of 12 balls, and suppose that two groups are formed. Group A contains 4 balls and Group B contains 8 balls. (a) How many different ways are there to form these two groups? (b) Now suppose that 5 of the 12 balls are red and 3 of these are in Group A. In this case, how many different ways are there to form the two groups? Fisher’s exact test can be used to determine whether the red balls tend to be clustered in one group more than we would expect by chance.