condition mean min max ZT0-3 12.857 12.857 12.857 ZT4-7 7.84483 7.84483 7.84483 ZT8-11 22.4429 22.4429 22.4429 ZT12-15 38.350049999999996 38.350049999999996 38.350049999999996 ZT16-19 32.1947 32.1947 32.1947 ZT20-23 16.74175 16.74175 16.74175