condition mean min max ZT0-3 14.341833333333334 13.17845 16.2165 ZT4-7 7.44365 7.44365 7.44365 ZT8-11 7.6048849999999995 7.6048849999999995 7.6048849999999995 ZT12-15 25.255475 13.69505 36.8159 ZT16-19 21.99455 21.99455 21.99455 ZT20-23 20.95245 20.95245 20.95245