condition mean min max ZT0-3 8.202079999999999 8.202079999999999 8.202079999999999 ZT4-7 5.375675 5.375675 5.375675 ZT8-11 6.1700099999999996 6.1700099999999996 6.1700099999999996 ZT12-15 9.013215 9.013215 9.013215 ZT16-19 14.80685 14.80685 14.80685 ZT20-23 11.41025 11.41025 11.41025