The article "Birth Order and Political Success" (Psych. Reports, 1971: 1239-1242) reports that among 31 randomly selected candidates for political office who came from families with four children, 12 were firstborn, 11 were middle born, and 8 were last born. Use this data to test the null hypothesis that a political candidate from such a family is equally likely to be in any one of the four ordinal positions.