condition mean min max ZT0-3 7.554390000000001 7.554390000000001 7.554390000000001 ZT4-7 7.0485750000000005 7.0485750000000005 7.0485750000000005 ZT8-11 5.09212 5.09212 5.09212 ZT12-15 4.538325 4.538325 4.538325 ZT16-19 5.70155 5.70155 5.70155 ZT20-23 6.5107566666666665 6.5107566666666665 6.5107566666666665