condition mean min max ZT0-3 8.952085 8.952085 8.952085 ZT4-7 8.4406335 8.4406335 8.4406335 ZT8-11 8.55724 8.55724 8.55724 ZT12-15 8.569893 8.569893 8.569893 ZT16-19 8.848075999999999 8.848075999999999 8.848075999999999 ZT20-23 8.754415999999999 8.754415999999999 8.754415999999999