I am 19 years old, 5'3"male, 131 pounds, East African of origin. Recently, it came to my attention that there are some ways to predict and measure height, such as the arm span to height ratio (approximately one to one) and the femur to height ratio was (approximately one to four). So, I decided to measure my arm span, which came out to be 6.5feet. I thought I made a mistake so I remeasured it again along with my femur height (1.5feet). I don't know what this means. And would appreciate any help in figuring it out.
Also: My mother is 4'11" and I don't know my dad's height. But my younger brother is 5'8" already and he is just 15.