These three quotes talk about the use of the Poisson and normal distributions as approximations for the binomial when n is large. The first two quotes here say Poisson is best when p small, and the normal otherwise. The third seems to change the story; it says Poisson is best for large p too. Is there a contradiction here, or is Hoel just nuancing it as he goes along? - Hoel: Introduction to Mathematical Statistics, 5th ed., p. 64. - Hoel: ibid., p. 81. - Hoel: ibid., p. 85.