condition mean min max ZT0-3 3.2308408257499996 3.1233159844999996 3.3383656669999997 ZT4-7 1.92746254975 1.9264112795 1.92851382 ZT8-11 1.7534307485 1.400237434 2.106624063 ZT12-15 3.98181059925 3.5421911565 4.421430042000001 ZT16-19 5.8129859785 5.406291869 6.2196800880000005 ZT20-23 8.1501286915 8.129257436 8.170999947