condition mean min max ZT0-3 10.207365 9.72598 10.688749999999999 ZT4-7 7.517555 7.517555 7.517555 ZT8-11 12.03405 12.03405 12.03405 ZT12-15 0 0 0 ZT16-19 14.8293 14.8293 14.8293 ZT20-23 12.3164 12.3164 12.3164