condition mean min max ZT0-3 10.591361666666666 8.9427 12.4452 ZT4-7 9.271555 9.271555 9.271555 ZT8-11 9.324069999999999 9.324069999999999 9.324069999999999 ZT12-15 7.7854625 6.051505000000001 9.51942 ZT16-19 10.785505 10.785505 10.785505 ZT20-23 7.57089 7.57089 7.57089