condition mean min max ZT0-3 4.8601366666666665 3.10111 6.477785 ZT4-7 4.59223 4.59223 4.59223 ZT8-11 3.3699250000000003 3.3699250000000003 3.3699250000000003 ZT12-15 2.5686575 1.860105 3.27721 ZT16-19 3.62805 3.62805 3.62805 ZT20-23 4.026104999999999 4.026104999999999 4.026104999999999