condition mean min max ZT0-3 14.328925 11.81355 16.8443 ZT4-7 8.465164999999999 8.465164999999999 8.465164999999999 ZT8-11 9.0165 9.0165 9.0165 ZT12-15 0 0 0 ZT16-19 13.8058 13.8058 13.8058 ZT20-23 12.270399999999999 12.270399999999999 12.270399999999999