condition mean min max ZT0-3 70.128659 70.128659 70.128659 ZT4-7 65.243776 65.243776 65.243776 ZT8-11 76.341725 76.341725 76.341725 ZT12-15 109.05043 109.05043 109.05043 ZT16-19 142.4576615 142.4576615 142.4576615 ZT20-23 213.8029795 213.8029795 213.8029795