In the 19th century, most books quoted "blood heat" as 98 F, until a study published the mean (but not the variance) of a large sample as 36.88 °C. Subsequently, that mean was widely quoted as "37 C”. This translates to 98.6 F. (Wikipedia) In a recent study of 148 healthy men and women ages 18-40 years, participating in the Shigella Vaccine Trials at the University of Maryland Center for Vaccine Development, had oral temperatures measured 1-4 times daily for three consecutive days using an electronic digital thermometer. The mean observed oral temperature was 36.8 C which translates to 98.2 F, with a standard deviation of 0.62 F. (Altern Med Rev 2006;11(4):278-293) If you select a person at random from a population with body temperatures that are N(98.2,0.62)… 4. Use the empirical rule to determine the probability that the body temperature is larger than 99.44. Round to 4 decimal places