condition mean min max ZT0-3 2.154795 2.154795 2.154795 ZT4-7 2.07818 2.07818 2.07818 ZT8-11 1.379915 1.379915 1.379915 ZT12-15 1.7663 1.7663 1.7663 ZT16-19 1.5315400000000001 1.5315400000000001 1.5315400000000001 ZT20-23 1.682705 1.682705 1.682705