condition mean min max ZT0-3 1.3932733333333334 1.104755 1.9588400000000001 ZT4-7 1.26535 1.26535 1.26535 ZT8-11 1.38666 1.38666 1.38666 ZT12-15 2.1364 2.0885 2.1843000000000004 ZT16-19 1.6247099999999999 1.6247099999999999 1.6247099999999999 ZT20-23 1.791515 1.791515 1.791515