PDA

View Full Version : ASM (5th ed.) 37.1 - D(x) plot

Blue Like Jazz
10-20-2007, 09:28 AM
This problem has a D(x) plot and then asks which regions have too much weight. The pattern is saw-toothed with vertical lines (point mass type of thing) at various points and then declining as x increases to the next point.

The solution indicates that when there is a net decline over the region, then there is too much weight. I'm confused about whether that decline is from the higher value or the lower value at each of the point masses.

For instance, region IV (300-400) has a vertical line from -0.5 to 0.5 at 300. The solution uses the higher value as the starting point showing a decline from 0.5 to 0. However, in region III it seems to do the opposite.

Could anyone clear this up for me? Thanks!

Abraham Weishaus
10-20-2007, 08:16 PM
In region III, whether you go from the top to the top or the bottom to the bottom, you reach the same conclusion, so the problem is self-consistent, unless you interpret the intervals to all be open intervals.

However, I agree it was a bad idea to put observations at the borders of the regions, making the problem ambiguous. I will change the problem for the next edition.