condition mean min max ZT0-3 2.5184583333333332 1.69919 3.8474 ZT4-7 1.77444 1.77444 1.77444 ZT8-11 6.471315000000001 6.471315000000001 6.471315000000001 ZT12-15 13.83305 11.30965 16.35645 ZT16-19 7.998985 7.998985 7.998985 ZT20-23 7.80363 7.80363 7.80363