condition mean min max ZT0-3 3.9129224999999996 3.60674 4.219105 ZT4-7 4.563795000000001 4.563795000000001 4.563795000000001 ZT8-11 6.0047999999999995 6.0047999999999995 6.0047999999999995 ZT12-15 0 0 0 ZT16-19 5.336 5.336 5.336 ZT20-23 5.70648 5.70648 5.70648