condition mean min max ZT0-3 24.101635 16.36822 31.83505 ZT4-7 15.449275 15.449275 15.449275 ZT8-11 23.68075 23.68075 23.68075 ZT12-15 0 0 0 ZT16-19 20.881 20.881 20.881 ZT20-23 33.7645 33.7645 33.7645