condition mean min max ZT0-3 4.822038333333333 4.1605 5.484055 ZT4-7 4.0241 4.0241 4.0241 ZT8-11 4.350820000000001 4.350820000000001 4.350820000000001 ZT12-15 5.5149799999999995 5.3422 5.68776 ZT16-19 5.101084999999999 5.101084999999999 5.101084999999999 ZT20-23 6.030885 6.030885 6.030885