condition mean min max ZT0-3 11.940086 11.940086 11.940086 ZT4-7 11.4484315 11.4484315 11.4484315 ZT8-11 11.855684499999999 11.855684499999999 11.855684499999999 ZT12-15 12.294998 12.294998 12.294998 ZT16-19 12.308268 12.308268 12.308268 ZT20-23 11.8405975 11.8405975 11.8405975