condition mean min max ZT0-3 9.363103 9.363103 9.363103 ZT4-7 10.5963635 10.5963635 10.5963635 ZT8-11 13.041064500000001 13.041064500000001 13.041064500000001 ZT12-15 12.045755 12.045755 12.045755 ZT16-19 15.159689 15.159689 15.159689 ZT20-23 11.980419999999999 11.980419999999999 11.980419999999999