condition mean min max ZT0-3 3.4220833333333336 1.9139 4.344335 ZT4-7 1.720045 1.720045 1.720045 ZT8-11 2.030265 2.030265 2.030265 ZT12-15 2.4777325 2.267405 2.68806 ZT16-19 2.098135 2.098135 2.098135 ZT20-23 3.18269 3.18269 3.18269