condition mean min max ZT0-3 17.228482 17.228482 17.228482 ZT4-7 19.5286665 19.5286665 19.5286665 ZT8-11 19.0236085 19.0236085 19.0236085 ZT12-15 16.025708 16.025708 16.025708 ZT16-19 17.6294975 17.6294975 17.6294975 ZT20-23 20.2163075 20.2163075 20.2163075