condition mean min max ZT0-3 10.160251666666667 5.28409 14.74015 ZT4-7 8.21602 8.21602 8.21602 ZT8-11 8.54918 8.54918 8.54918 ZT12-15 20.89435 15.065249999999999 26.72345 ZT16-19 11.366900000000001 11.366900000000001 11.366900000000001 ZT20-23 19.3171 19.3171 19.3171