condition mean min max ZT0-3 11.0517 11.0517 11.0517 ZT4-7 7.46492 7.46492 7.46492 ZT8-11 9.959515 9.959515 9.959515 ZT12-15 18.37315 18.37315 18.37315 ZT16-19 18.2243 18.2243 18.2243 ZT20-23 13.061150000000001 13.061150000000001 13.061150000000001