<prompt> Berkesonian bias refers to -Bias arsing from different rates of admission to the hospitalBias arising from presence of confounding factorsBias arising from the case not being representative of general populationBias arising from improper selection of cases  <response>: This special example of berkesonian bias is termed after Dr. Joseph Berkesonian who recognized this problem. Ref: 25th edition, Parks Textbook of Preventive and Social Medicine, Page no. 81, 82 