condition mean min max ZT0-3 8.112335 8.112335 8.112335 ZT4-7 5.389235 5.389235 5.389235 ZT8-11 7.88075 7.88075 7.88075 ZT12-15 7.629995 7.629995 7.629995 ZT16-19 9.127875 9.127875 9.127875 ZT20-23 7.96725 7.96725 7.96725