condition mean min max ZT0-3 8.719135 8.719135 8.719135 ZT4-7 3.37822 3.37822 3.37822 ZT8-11 1.8364850000000001 1.8364850000000001 1.8364850000000001 ZT12-15 3.1252500000000003 3.1252500000000003 3.1252500000000003 ZT16-19 2.373775 2.373775 2.373775 ZT20-23 5.84776 5.84776 5.84776