condition mean min max ZT0-3 12.270475 11.7423 12.798649999999999 ZT4-7 16.4023 16.4023 16.4023 ZT8-11 7.169115 7.169115 7.169115 ZT12-15 0 0 0 ZT16-19 9.65285 9.65285 9.65285 ZT20-23 14.59505 14.59505 14.59505