condition mean min max ZT0-3 0.306088 0.306088 0.306088 ZT4-7 0.249166 0.249166 0.249166 ZT8-11 0.349825 0.349825 0.349825 ZT12-15 0.352587 0.352587 0.352587 ZT16-19 0.3314225 0.3314225 0.3314225 ZT20-23 0.356794 0.356794 0.356794