condition mean min max ZT0-3 1434.307195 1434.307195 1434.307195 ZT4-7 1901.8648865 1901.8648865 1901.8648865 ZT8-11 1158.3665645 1158.3665645 1158.3665645 ZT12-15 666.824328 666.824328 666.824328 ZT16-19 746.8227059999999 746.8227059999999 746.8227059999999 ZT20-23 985.4364515 985.4364515 985.4364515