The ash remaining represents very roughly 3.5% of the body's original mass (2.5% in children). Because the weight of dry bone fragments is so closely connected to skeletal mass, their weight varies greatly from person to person. Because many changes in body composition (such as fat and muscle loss or gain) do not affect the weight of cremated remains, the weight of the remains can be more closely predicted from the person's height and sex (which predicts skeletal weight), than it can be predicted from the person's simple weight.