condition mean min max ZT0-3 4.339271666666667 2.82073 5.223535 ZT4-7 2.224355 2.224355 2.224355 ZT8-11 3.06046 3.06046 3.06046 ZT12-15 3.0995825 2.5525349999999998 3.64663 ZT16-19 2.878155 2.878155 2.878155 ZT20-23 4.398365 4.398365 4.398365