condition mean min max ZT0-3 21.326217 21.326217 21.326217 ZT4-7 23.907955 23.907955 23.907955 ZT8-11 23.973365 23.973365 23.973365 ZT12-15 24.8216395 24.8216395 24.8216395 ZT16-19 23.049884 23.049884 23.049884 ZT20-23 24.50969 24.50969 24.50969