condition mean min max ZT0-3 8.11398 8.11398 8.11398 ZT4-7 6.19139 6.19139 6.19139 ZT8-11 7.704364999999999 7.704364999999999 7.704364999999999 ZT12-15 10.090765000000001 10.090765000000001 10.090765000000001 ZT16-19 12.6464 12.6464 12.6464 ZT20-23 9.530245 9.530245 9.530245