condition mean min max ZT0-3 1.6799707105000001 1.423948906 1.9359925150000001 ZT4-7 3.2667922789999997 2.4964853959999997 4.037099162 ZT8-11 4.52743171925 4.209779542 4.8450838965 ZT12-15 4.4309184645 4.326691994500001 4.5351449345 ZT16-19 4.901814691 4.303290961 5.500338421 ZT20-23 7.861444574499999 7.452792973999999 8.270096174999999