condition mean min max ZT0-3 6.150275 6.150275 6.150275 ZT4-7 6.329925 6.329925 6.329925 ZT8-11 7.06029 7.06029 7.06029 ZT12-15 6.74022 6.74022 6.74022 ZT16-19 4.761995 4.761995 4.761995 ZT20-23 5.70448 5.70448 5.70448