obtaining a mean value and {HEAD ~ a standard deviation} from {TAIL ~ said mean value} for one of said measured characteristics 
from
obtaining a mean value and { HEAD ~ a standard deviation } from { TAIL ~ said mean value } for one of said measured characteristics
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH