condition mean min max ZT0-3 1.63718720425 1.186413507 2.0879609015 ZT4-7 3.3928301672499996 2.3410324965 4.444627838 ZT8-11 7.10312711125 5.766469432999999 8.4397847895 ZT12-15 8.036633740500001 7.763208165 8.310059316 ZT16-19 7.3263880089999995 6.804387720499999 7.8483882975 ZT20-23 8.3842370435 8.184471164 8.584002923