condition mean min max ZT0-3 6.70883 6.70883 6.70883 ZT4-7 5.402835 5.402835 5.402835 ZT8-11 4.42309 4.42309 4.42309 ZT12-15 5.93663 5.93663 5.93663 ZT16-19 14.3923 14.3923 14.3923 ZT20-23 7.483305 7.483305 7.483305