condition mean min max ZT0-3 13.861021666666668 7.232315 17.86135 ZT4-7 8.98169 8.98169 8.98169 ZT8-11 7.467795000000001 7.467795000000001 7.467795000000001 ZT12-15 9.383457499999999 8.390564999999999 10.37635 ZT16-19 11.64385 11.64385 11.64385 ZT20-23 21.8759 21.8759 21.8759