condition mean min max ZT0-3 7.97553 7.97553 7.97553 ZT4-7 8.37956 8.37956 8.37956 ZT8-11 6.0041 6.0041 6.0041 ZT12-15 5.76414 5.76414 5.76414 ZT16-19 6.50901 6.50901 6.50901 ZT20-23 7.592755 7.592755 7.592755