condition mean min max ZT0-3 5.673263333333334 5.3523 6.05377 ZT4-7 4.60346 4.60346 4.60346 ZT8-11 7.685840000000001 7.685840000000001 7.685840000000001 ZT12-15 7.7226574999999995 6.7710799999999995 8.674235 ZT16-19 6.959935 6.959935 6.959935 ZT20-23 9.121894999999999 9.121894999999999 9.121894999999999