condition mean min max ZT0-3 996.373957 996.373957 996.373957 ZT4-7 589.546685 589.546685 589.546685 ZT8-11 689.000709 689.000709 689.000709 ZT12-15 868.145815 868.145815 868.145815 ZT16-19 1085.288571 1085.288571 1085.288571 ZT20-23 1036.9250785 1036.9250785 1036.9250785