condition mean min max ZT0-3 173.164753 173.164753 173.164753 ZT4-7 308.8932645 308.8932645 308.8932645 ZT8-11 365.959572 365.959572 365.959572 ZT12-15 367.17764999999997 367.17764999999997 367.17764999999997 ZT16-19 272.30278450000003 272.30278450000003 272.30278450000003 ZT20-23 194.506079 194.506079 194.506079