What is the ratio of head to waist and waist to floor of the human anatomy?
The study of those measures is called anthropometry. Typing anthropometry on google image returned this



This is definitely not a peer-review source and might eventually be a good approximation only for white males (or whoever they considered to take these measurements on) but if we believe this image, then the ratio head-to-waist over waist-to-floor is $\frac{0.52}{0.485} = 1.072$.