condition mean min max ZT0-3 6.709595 6.4026250000000005 7.016565 ZT4-7 4.84238 4.84238 4.84238 ZT8-11 6.286245 6.286245 6.286245 ZT12-15 0 0 0 ZT16-19 7.93168 7.93168 7.93168 ZT20-23 4.069075 4.069075 4.069075