I have been a faithful reader of your column, and I have not, until now, had any reason to doubt you. However, in this matter (for which I do have expertise), your answer is clearly at odds with the truth. James Rauff, Ph.D. Millikin University

May I suggest that you obtain and refer to a standard textbook on probability before you try to answer a question of this type again? Charles Reid, Ph.D. University of Florida

You made a mistake, but look at the positive side. If all those Ph.D.’s were wrong, the country would be in some very serious trouble. Everett Harman, Ph.D. U.S. Army Research Institute