condition mean min max ZT0-3 10.391312 10.391312 10.391312 ZT4-7 11.853624 11.853624 11.853624 ZT8-11 12.591089499999999 12.591089499999999 12.591089499999999 ZT12-15 12.8940385 12.8940385 12.8940385 ZT16-19 13.305147999999999 13.305147999999999 13.305147999999999 ZT20-23 11.6068705 11.6068705 11.6068705