condition mean min max ZT0-3 10.026089 10.026089 10.026089 ZT4-7 11.920136 11.920136 11.920136 ZT8-11 11.189437 11.189437 11.189437 ZT12-15 11.4323915 11.4323915 11.4323915 ZT16-19 11.084212999999998 11.084212999999998 11.084212999999998 ZT20-23 9.9637335 9.9637335 9.9637335