condition mean min max ZT0-3 4.268015 4.268015 4.268015 ZT4-7 5.4093599999999995 5.4093599999999995 5.4093599999999995 ZT8-11 2.5730500000000003 2.5730500000000003 2.5730500000000003 ZT12-15 11.157665 11.157665 11.157665 ZT16-19 11.84343 11.84343 11.84343 ZT20-23 9.36782 9.36782 9.36782