condition mean min max ZT0-3 4.019723333333333 3.288935 5.0916999999999994 ZT4-7 3.29289 3.29289 3.29289 ZT8-11 3.44725 3.44725 3.44725 ZT12-15 4.294957500000001 3.6904000000000003 4.899515 ZT16-19 5.53819 5.53819 5.53819 ZT20-23 5.030725 5.030725 5.030725