condition mean min max ZT0-3 4.991555 4.652495 5.330615 ZT4-7 5.07168 5.07168 5.07168 ZT8-11 5.607049999999999 5.607049999999999 5.607049999999999 ZT12-15 0 0 0 ZT16-19 8.424485 8.424485 8.424485 ZT20-23 7.53163 7.53163 7.53163