condition mean min max ZT0-3 10.25 10.25 10.25 ZT4-7 5.2 5.2 5.2 ZT8-11 16.2 16.2 16.2 ZT12-15 11.55 11.55 11.55 ZT16-19 4.949999999999999 4.949999999999999 4.949999999999999 ZT20-23 18.75 18.75 18.75