condition mean min max ZT0-3 15.859358 15.859358 15.859358 ZT4-7 12.850601 12.850601 12.850601 ZT8-11 11.8632475 11.8632475 11.8632475 ZT12-15 13.4118685 13.4118685 13.4118685 ZT16-19 12.196427 12.196427 12.196427 ZT20-23 15.210808499999999 15.210808499999999 15.210808499999999