condition mean min max ZT0-3 4.991295 4.991295 4.991295 ZT4-7 5.325195 5.325195 5.325195 ZT8-11 4.80096 4.80096 4.80096 ZT12-15 6.196895 6.196895 6.196895 ZT16-19 7.063395 7.063395 7.063395 ZT20-23 5.379945 5.379945 5.379945