condition mean min max ZT0-3 8.688535 7.607575 9.769495 ZT4-7 7.26434 7.26434 7.26434 ZT8-11 11.4271 11.4271 11.4271 ZT12-15 0 0 0 ZT16-19 11.24905 11.24905 11.24905 ZT20-23 6.75054 6.75054 6.75054