condition mean min max ZT0-3 9.236519999999999 9.236519999999999 9.236519999999999 ZT4-7 7.47082 7.47082 7.47082 ZT8-11 8.77209 8.77209 8.77209 ZT12-15 7.953720000000001 7.953720000000001 7.953720000000001 ZT16-19 11.057 11.057 11.057 ZT20-23 9.90739 9.90739 9.90739