Displacement of an object that will float measures weight. The displacement of a submerged object can only provide information about volume.
Which was never ever the point in the first place. The entire reason for the procedure is to get an idea of what a person’s body fat percentage is. Measuring volume is but one of the steps, the final step in the calculations is geting the body fat MASS percentage.
js would know this if he simply took the time to digest what he reads.
You are making progress here.
Now all you have to do is admit that floating people in water is not the ususal and customary method of weighing them. The only reason water is used is to measure volume.
All you have to ask yourself is, when was the last time doctor not interested in your body fat percentage asked you to float in water so he could find your wight.