condition mean min max ZT0-3 18.1453640475 16.73241357 19.558314525 ZT4-7 17.327135315 16.61224995 18.04202068 ZT8-11 21.164013075 20.84740443 21.48062172 ZT12-15 18.070581375 14.946952909999998 21.19420984 ZT16-19 21.213557121666668 20.713925046666667 21.713189196666665 ZT20-23 20.240274088333333 19.515563473333334 20.964984703333332