condition mean min max ZT0-3 3.80770869 2.7287510669999997 4.886666313 ZT4-7 7.88406310275 7.684845828 8.0832803775 ZT8-11 6.18380267575 4.992487243999999 7.3751181075 ZT12-15 3.89664722975 2.5955294325000002 5.197765027 ZT16-19 3.3560438242499995 2.9155503565 3.7965372919999996 ZT20-23 2.6438189992500005 2.103057623 3.1845803755000004