condition mean min max ZT0-3 7.319175 7.013835 7.624515000000001 ZT4-7 7.4722 7.4722 7.4722 ZT8-11 11.83905 11.83905 11.83905 ZT12-15 0 0 0 ZT16-19 15.139800000000001 15.139800000000001 15.139800000000001 ZT20-23 12.9817 12.9817 12.9817