OK, simply put, this separates all of the units into 12 groups
Now change those days to a value, and separate that 18 into equal twelths, and then you have 12 classes by drawing a line from the twelths, to the curving line, and then down. So, the area to the left of one of these downward lines would be the the area covered by the duodecile (twelth of the range)
Now change those days to a value, and separate that 18 into equal twelths, and then you have 12 classes by drawing a line from the twelths, to the curving line, and then down. So, the area to the left of one of these downward lines would be the the area covered by the duodecile (twelth of the range)
Comment