condition mean min max ZT0-3 19.883200000000002 16.80595 22.96045 ZT4-7 12.40615 12.40615 12.40615 ZT8-11 9.018529999999998 9.018529999999998 9.018529999999998 ZT12-15 0 0 0 ZT16-19 11.092600000000001 11.092600000000001 11.092600000000001 ZT20-23 12.17835 12.17835 12.17835