condition mean min max ZT0-3 206.598322 206.598322 206.598322 ZT4-7 267.871854 267.871854 267.871854 ZT8-11 281.208941 281.208941 281.208941 ZT12-15 281.07563 281.07563 281.07563 ZT16-19 340.5495175 340.5495175 340.5495175 ZT20-23 301.580534 301.580534 301.580534