condition mean min max ZT0-3 12.375502 12.375502 12.375502 ZT4-7 18.830697 18.830697 18.830697 ZT8-11 17.511738 17.511738 17.511738 ZT12-15 13.5331565 13.5331565 13.5331565 ZT16-19 15.56358 15.56358 15.56358 ZT20-23 14.984206 14.984206 14.984206