condition mean min max ZT0-3 9.039348 9.039348 9.039348 ZT4-7 9.248625 9.248625 9.248625 ZT8-11 8.901485 8.901485 8.901485 ZT12-15 7.97446 7.97446 7.97446 ZT16-19 8.3361735 8.3361735 8.3361735 ZT20-23 9.50561 9.50561 9.50561