Chapter 3.1, Problem 8E

(a)

To determine

To describe: the direction, form, and strength of the relationship

Answer to Problem 8E

Direction: negative

Form: linear

Strength: moderately strong.

Explanation of Solution

Calculation:

Take percent return (the explanatory variable) on the horizontal axis and new adults (the response variable) on the vertical axis. Below figure is our completed scatterplot.

  

The graph shows a negative direction: the overall pattern moves from upper left to lower right. That is, states in which lower percent return tend to have higher new adult birds that join the colony. We call this a negative association between the two variables. The form of the relationship is linear. That is, the overall pattern follows a straight line from upper left to lower right. The relationship is moderately strong because the points don’t deviate greatly from line.

Conclusion:

Therefore,

Direction: negative

Form: linear

Strength: moderately strong.

(b)

To determine

To explain:the type of species which is the sparrow hawk

Answer to Problem 8E

Long lived territorial birds are the type of species which is the sparrow hawk

Explanation of Solution

Calculation:

The overall pattern moves from upper left to lower right. That is, states in which lower percent return tend to have higher new adult birds that join the colony. We call this a negative association between the two variables. Since, we know that for long lived territorial birds, the association is negative because returning birds claim their territories in the colony and don’t leave room for new recruit. These are long lived territorial birds.