condition mean min max ZT0-3 10.173615 10.173615 10.173615 ZT4-7 9.023226999999999 9.023226999999999 9.023226999999999 ZT8-11 8.4702265 8.4702265 8.4702265 ZT12-15 8.1779415 8.1779415 8.1779415 ZT16-19 9.875931 9.875931 9.875931 ZT20-23 8.941825999999999 8.941825999999999 8.941825999999999