condition mean min max ZT0-3 7.179433 7.179433 7.179433 ZT4-7 8.3963965 8.3963965 8.3963965 ZT8-11 10.34253 10.34253 10.34253 ZT12-15 9.552441 9.552441 9.552441 ZT16-19 10.977503500000001 10.977503500000001 10.977503500000001 ZT20-23 9.164192 9.164192 9.164192