condition mean min max ZT0-3 8.833406 8.833406 8.833406 ZT4-7 9.580126499999999 9.580126499999999 9.580126499999999 ZT8-11 8.914159000000001 8.914159000000001 8.914159000000001 ZT12-15 8.0134795 8.0134795 8.0134795 ZT16-19 9.1878515 9.1878515 9.1878515 ZT20-23 8.503569 8.503569 8.503569