condition mean min max ZT0-3 1.8032703333333335 1.0425710000000001 2.442985 ZT4-7 0.8594489999999999 0.8594489999999999 0.8594489999999999 ZT8-11 1.2837465 1.2837465 1.2837465 ZT12-15 2.09358 2.061435 2.125725 ZT16-19 2.75261 2.75261 2.75261 ZT20-23 3.177045 3.177045 3.177045