condition mean min max ZT0-3 14.966684 14.966684 14.966684 ZT4-7 13.480058 13.480058 13.480058 ZT8-11 16.2572975 16.2572975 16.2572975 ZT12-15 16.211606500000002 16.211606500000002 16.211606500000002 ZT16-19 25.185381 25.185381 25.185381 ZT20-23 36.951647 36.951647 36.951647