Derivation
variable: weight (table[s]: this dataset)
variable: ffmass_R (table[s]: this dataset)
variable: dropped_R (table[s]: this dataset)
gen ffmasspc_R=100*(ffmass_R/weight) if weight~=. & ffmass_R~=.
<remove inconsistent data from combined data:>
foreach var in fatmass_R fatmasspc_R ffmass_R ffmasspc_R {
replace `var'=. if dropped_R==1
}