condition mean min max ZT0-3 14.714068333333334 7.464905 23.4026 ZT4-7 9.01596 9.01596 9.01596 ZT8-11 11.834 11.834 11.834 ZT12-15 23.214425 19.61375 26.8151 ZT16-19 23.020699999999998 23.020699999999998 23.020699999999998 ZT20-23 27.59405 27.59405 27.59405