Suppose 300 persons are selected at random from a large population; and that each person in the sample is classified according to whether his/her blood type is O, A, B, or AB, and also according to whether his/her blood type is Rh-positive or Rh-negative. The observed table is:

Observed counts

O A B AB

Rh +82 89 54 19

Rh - 13 27 7 9

Test the hypothesis that the two classifications of blood types are independent.

Null hypothesis: RH designation and blood type are independent

Alternative hypothesis: RH designation and blood type are NOT independent