condition mean min max ZT0-3 5.8510925 5.7461649999999995 5.9560200000000005 ZT4-7 6.37064 6.37064 6.37064 ZT8-11 7.09023 7.09023 7.09023 ZT12-15 0 0 0 ZT16-19 7.683870000000001 7.683870000000001 7.683870000000001 ZT20-23 6.5731850000000005 6.5731850000000005 6.5731850000000005