Question

A certain population of beavers builds dams across a stream to catch fish. Some years the stream carries more water than other years. The data below was collected by scientists studying the stream over a sixteen year period.

Years Average Stream Depth
(meters) Average Number of
Beaver Dams Average Number of
Beavers
2000-2003 1.20 6 17
2004-2007 0.92 4 12
2008-2011 1.45 7 21
2012-2015 0.78 2 9

If the average depth of the stream for the next 4 years is 1.60 meters, which of the following is most likely to occur?
A.
The average size of a beaver dam will decrease.
B.
The size of the beaver population will decrease.
C.
The size of the beaver population will increase.
D.
The average size of each beaver will increase.

Answer 1

To make an inference about what might happen if the average depth of the stream increases to 1.60 meters, we can analyze the historical data provided.

From the data:

- In periods with higher average stream depth (e.g., 2008-2011 with 1.45 m), the average number of beaver dams (7) and average number of beavers (21) were higher compared to periods with lower depths.
- Conversely, during periods with lower stream depths (e.g., 2012-2015 with 0.78 m), the number of beaver dams (2) and beavers (9) decreased.

Given that an increase in stream depth has historically corresponded to more beaver dams and a larger beaver population, it is reasonable to conclude that if the average stream depth increases to 1.60 meters, the beaver population is likely to increase as well.

Therefore, the most likely outcome is:

C. The size of the beaver population will increase.