condition mean min max ZT0-3 5.68968 5.68968 5.68968 ZT4-7 6.13497 6.13497 6.13497 ZT8-11 6.20852 6.20852 6.20852 ZT12-15 8.07938 8.07938 8.07938 ZT16-19 11.2281 11.2281 11.2281 ZT20-23 12.422600000000001 12.422600000000001 12.422600000000001