condition mean min max ZT0-3 1.681308 1.681308 1.681308 ZT4-7 3.2150873333333334 3.2150873333333334 3.2150873333333334 ZT8-11 3.507064 3.507064 3.507064 ZT12-15 7.921359 7.921359 7.921359 ZT16-19 6.070337 6.070337 6.070337 ZT20-23 3.7411939999999997 3.7411939999999997 3.7411939999999997