According to the national center for health statistics, the mean height of an american male is 69.3 inches and the mean height of an american female is 63.8 inches. the standard deviation for both genders is 2.7 inches. according to chebyshev’s theorem , what heights for your gender mark the 75% data values? if height is assumed to be normal what percentages lies between those two heights?

i'm not really sure how to do this one. don't you use the formula (mean+- 2*(standard why is it that some do the problem like this (mean+- 1.14* (standard deviation)