condition mean min max ZT0-3 2.8932366666666667 1.607625 3.7906999999999997 ZT4-7 0.9624205 0.9624205 0.9624205 ZT8-11 1.894395 1.894395 1.894395 ZT12-15 3.9685375 3.6125249999999998 4.32455 ZT16-19 3.7737100000000003 3.7737100000000003 3.7737100000000003 ZT20-23 4.949465 4.949465 4.949465