condition mean min max ZT0-3 609.154467 609.154467 609.154467 ZT4-7 314.8269785 314.8269785 314.8269785 ZT8-11 157.43606 157.43606 157.43606 ZT12-15 185.6310065 185.6310065 185.6310065 ZT16-19 24.528596999999998 24.528596999999998 24.528596999999998 ZT20-23 30.322736000000003 30.322736000000003 30.322736000000003