condition mean min max ZT0-3 215.955542 215.955542 215.955542 ZT4-7 222.70621749999998 222.70621749999998 222.70621749999998 ZT8-11 278.141347 278.141347 278.141347 ZT12-15 253.6145725 253.6145725 253.6145725 ZT16-19 243.51961649999998 243.51961649999998 243.51961649999998 ZT20-23 272.338334 272.338334 272.338334