condition mean min max ZT0-3 431.674166 431.674166 431.674166 ZT4-7 436.9668445 436.9668445 436.9668445 ZT8-11 473.56995199999994 473.56995199999994 473.56995199999994 ZT12-15 501.31089099999997 501.31089099999997 501.31089099999997 ZT16-19 483.429512 483.429512 483.429512 ZT20-23 438.763554 438.763554 438.763554