condition mean min max ZT0-3 8.306875 8.306875 8.306875 ZT4-7 5.206995 5.206995 5.206995 ZT8-11 5.5276 5.5276 5.5276 ZT12-15 7.849130000000001 7.849130000000001 7.849130000000001 ZT16-19 11.005780000000001 11.005780000000001 11.005780000000001 ZT20-23 9.639565 9.639565 9.639565