condition mean min max ZT0-3 2.4655833333333335 2.16953 2.7601250000000004 ZT4-7 2.949855 2.949855 2.949855 ZT8-11 2.45031 2.45031 2.45031 ZT12-15 3.62098 3.1269 4.11506 ZT16-19 2.71328 2.71328 2.71328 ZT20-23 3.8623700000000003 3.8623700000000003 3.8623700000000003