condition mean min max ZT0-3 0.853815 0.408234 1.299396 ZT4-7 1.6489075 1.6489075 1.6489075 ZT8-11 0.714915 0.714915 0.714915 ZT12-15 0 0 0 ZT16-19 2.208335 2.208335 2.208335 ZT20-23 3.729275 3.729275 3.729275