condition mean min max ZT0-3 17.868225 15.76685 19.9696 ZT4-7 16.00395 16.00395 16.00395 ZT8-11 11.6856 11.6856 11.6856 ZT12-15 0 0 0 ZT16-19 16.3969 16.3969 16.3969 ZT20-23 15.64735 15.64735 15.64735