condition mean min max ZT0-3 7.552676666666667 5.701725 8.852595 ZT4-7 7.775980000000001 7.775980000000001 7.775980000000001 ZT8-11 10.24336 10.24336 10.24336 ZT12-15 14.360792499999999 11.541585 17.18 ZT16-19 10.853850000000001 10.853850000000001 10.853850000000001 ZT20-23 8.379355 8.379355 8.379355