condition mean min max ZT0-3 7.051130000000001 7.051130000000001 7.051130000000001 ZT4-7 4.3812999999999995 4.3812999999999995 4.3812999999999995 ZT8-11 5.34493 5.34493 5.34493 ZT12-15 5.422275 5.422275 5.422275 ZT16-19 6.001265 6.001265 6.001265 ZT20-23 6.116905 6.116905 6.116905