condition mean min max ZT0-3 8.06681 8.06681 8.06681 ZT4-7 7.079715 7.079715 7.079715 ZT8-11 5.591415 5.591415 5.591415 ZT12-15 6.63097 6.63097 6.63097 ZT16-19 7.22609 7.22609 7.22609 ZT20-23 7.16955 7.16955 7.16955