Derivation
variable: grip_left_1_gs (table[s]: NUTdata_KAR, NUTdata_LLW)
variable: grip_left_2_gs (table[s]: NUTdata_KAR, NUTdata_LLW)
variable: grip_left_3_gs (table[s]: NUTdata_KAR, NUTdata_LLW)
variable: grip_left1 (table[s]: gap_combined)
variable: grip_left2 (table[s]: gap_combined)
variable: grip_left3 (table[s]: gap_combined)
<NUT data:>
egen hg_left=rowmean(grip_left_1_gs grip_left_2_gs grip_left_3_gs)
<GAP data:>
egen hg_left=rowmean(grip_left1 grip_left2 grip_left3)