condition mean min max ZT0-3 11.650925 11.07 12.23185 ZT4-7 20.4239 20.4239 20.4239 ZT8-11 16.1337 16.1337 16.1337 ZT12-15 0 0 0 ZT16-19 17.9932 17.9932 17.9932 ZT20-23 14.7315 14.7315 14.7315