condition mean min max ZT0-3 5.2845575 4.358155 6.21096 ZT4-7 17.444499999999998 17.444499999999998 17.444499999999998 ZT8-11 21.3627 21.3627 21.3627 ZT12-15 0 0 0 ZT16-19 18.496000000000002 18.496000000000002 18.496000000000002 ZT20-23 18.21375 18.21375 18.21375