condition mean min max ZT0-3 8.903424999999999 8.903424999999999 8.903424999999999 ZT4-7 6.56923 6.56923 6.56923 ZT8-11 6.939925000000001 6.939925000000001 6.939925000000001 ZT12-15 7.3136 7.3136 7.3136 ZT16-19 9.178899999999999 9.178899999999999 9.178899999999999 ZT20-23 8.504175 8.504175 8.504175