condition mean min max ZT0-3 3.033685 3.033685 3.033685 ZT4-7 2.776625 2.776625 2.776625 ZT8-11 2.54938 2.54938 2.54938 ZT12-15 3.29307 3.29307 3.29307 ZT16-19 4.544605 4.544605 4.544605 ZT20-23 3.48854 3.48854 3.48854