condition mean min max ZT0-3 2.24269 2.24269 2.24269 ZT4-7 1.69544 1.69544 1.69544 ZT8-11 1.73243 1.73243 1.73243 ZT12-15 1.307985 1.307985 1.307985 ZT16-19 2.57564 2.57564 2.57564 ZT20-23 1.666865 1.666865 1.666865