condition mean min max ZT0-3 249.705893 249.705893 249.705893 ZT4-7 239.836979 239.836979 239.836979 ZT8-11 222.4860015 222.4860015 222.4860015 ZT12-15 229.50115749999998 229.50115749999998 229.50115749999998 ZT16-19 274.97740999999996 274.97740999999996 274.97740999999996 ZT20-23 272.8013775 272.8013775 272.8013775