condition mean min max ZT0-3 11.791325 11.688649999999999 11.894 ZT4-7 4.827315 4.827315 4.827315 ZT8-11 6.8438099999999995 6.8438099999999995 6.8438099999999995 ZT12-15 0 0 0 ZT16-19 7.432335 7.432335 7.432335 ZT20-23 7.82584 7.82584 7.82584