In nutrition, the recommended daily allowance (RDA) of a vitamin is a number set by the government as a guide to anindividual's daily vitamin intake. Actually, vitamin needs vary drastically from person to person, but the needs are very closely approximated by a normal curve. To calculate the RDA, the government first finds the average need for vitamins among people in the population and then the standard deviation. The RDA is defined as the mean plus 2.5 times the standard deviation. Find the recommended daily allowance for a vitamin if the mean need and standard deviation are as follows. mean = 750 units standard deviation = 59 units.