condition mean min max ZT0-3 8.476265 8.476265 8.476265 ZT4-7 4.3695 4.3695 4.3695 ZT8-11 6.9015699999999995 6.9015699999999995 6.9015699999999995 ZT12-15 6.115205 6.115205 6.115205 ZT16-19 11.25415 11.25415 11.25415 ZT20-23 9.305990000000001 9.305990000000001 9.305990000000001