condition mean min max ZT0-3 265.513463 265.513463 265.513463 ZT4-7 222.4729125 222.4729125 222.4729125 ZT8-11 157.563913 157.563913 157.563913 ZT12-15 142.1693195 142.1693195 142.1693195 ZT16-19 192.157233 192.157233 192.157233 ZT20-23 227.208218 227.208218 227.208218