Diehr P, Cain K, Connell F, Volinn E. What is too much variation? The null hypothesis in small-area analysis. Health Serv Res. 1990 Feb;24(6):741-71.
Diehr P, Cain K, Connell F, Volinn E. What is too much variation? The null hypothesis in small-area analysis. Health Serv Res. 1990 Feb;24(6):741-71.