condition mean min max ZT0-3 38.233675 32.54875 43.9186 ZT4-7 18.318199999999997 18.318199999999997 18.318199999999997 ZT8-11 23.9514 23.9514 23.9514 ZT12-15 0 0 0 ZT16-19 26.061 26.061 26.061 ZT20-23 28.286 28.286 28.286