condition mean min max ZT0-3 1.1479983333333332 0.5275245000000001 2.07084 ZT4-7 0.2990425 0.2990425 0.2990425 ZT8-11 0.4265985 0.4265985 0.4265985 ZT12-15 0.4895135 0.2158875 0.7631395 ZT16-19 0.397203 0.397203 0.397203 ZT20-23 1.1403675 1.1403675 1.1403675