condition mean min max ZT0-3 344.693595 344.693595 344.693595 ZT4-7 253.512521 253.512521 253.512521 ZT8-11 257.620083 257.620083 257.620083 ZT12-15 341.495081 341.495081 341.495081 ZT16-19 248.77051849999998 248.77051849999998 248.77051849999998 ZT20-23 132.369409 132.369409 132.369409