condition mean min max ZT0-3 5.2353016666666665 3.32231 7.142315 ZT4-7 4.020605 4.020605 4.020605 ZT8-11 2.308555 2.308555 2.308555 ZT12-15 3.4004675 2.9215 3.879435 ZT16-19 3.0701400000000003 3.0701400000000003 3.0701400000000003 ZT20-23 5.033075 5.033075 5.033075