condition mean min max ZT0-3 6.753534999999999 6.753534999999999 6.753534999999999 ZT4-7 7.2432549999999996 7.2432549999999996 7.2432549999999996 ZT8-11 7.17986 7.17986 7.17986 ZT12-15 6.13892 6.13892 6.13892 ZT16-19 7.491445 7.491445 7.491445 ZT20-23 6.523785 6.523785 6.523785