condition mean min max ZT0-3 9.224409999999999 9.224409999999999 9.224409999999999 ZT4-7 7.61792 7.61792 7.61792 ZT8-11 6.6103749999999994 6.6103749999999994 6.6103749999999994 ZT12-15 7.15198 7.15198 7.15198 ZT16-19 8.087299999999999 8.087299999999999 8.087299999999999 ZT20-23 8.58576 8.58576 8.58576