condition mean min max ZT0-3 3.5603775 2.786195 4.33456 ZT4-7 2.364395 2.364395 2.364395 ZT8-11 4.799475 4.799475 4.799475 ZT12-15 0 0 0 ZT16-19 6.208410000000001 6.208410000000001 6.208410000000001 ZT20-23 6.806470000000001 6.806470000000001 6.806470000000001