condition mean min max ZT0-3 16.040537 16.040537 16.040537 ZT4-7 21.5137805 21.5137805 21.5137805 ZT8-11 24.004535 24.004535 24.004535 ZT12-15 22.0667915 22.0667915 22.0667915 ZT16-19 20.099351 20.099351 20.099351 ZT20-23 28.801029 28.801029 28.801029