condition mean min max ZT0-3 15.918728 15.918728 15.918728 ZT4-7 18.725296 18.725296 18.725296 ZT8-11 15.52768 15.52768 15.52768 ZT12-15 14.3465665 14.3465665 14.3465665 ZT16-19 15.479397500000001 15.479397500000001 15.479397500000001 ZT20-23 15.881339 15.881339 15.881339