condition mean min max ZT0-3 12.234433333333333 12.234433333333333 12.234433333333333 ZT4-7 6.523905 6.523905 6.523905 ZT8-11 5.0280000000000005 5.0280000000000005 5.0280000000000005 ZT12-15 8.66394 8.66394 8.66394 ZT16-19 14.850200000000001 14.850200000000001 14.850200000000001 ZT20-23 14.02135 14.02135 14.02135