The answer is Letter D - 84%
68% of the data is within +/- 1 SD from the mean = 59 to 7195% of the data is within +/- 2 SDs from the mean = 53 to 7799.7% of the data is within +/- 3 SDs from the mean = 47 to 83
The whole 68% (59 - 71) scored below 71. Since the data are evenly distributed, we'll get the 32% (100 - 68) outside the range of 68% and divide it by 2 and add the quotient to the original 68% so that we'll get the total data below 71.
100 - 68 = 32
32 / 2 = 16
16 + 68 = 84
