Chapter 4.5, Problem 30E

To determine

To describe: The situation in a graph to be made, then to calculate correlation coefficient and elaborate if there is a causal relationship.

Answer to Problem 30E

The correlation coefficient is near about $0$ and this is not a causal relationship.

Explanation of Solution

Given information: Graph of number of people at two different beaches is to be created.

Calculation:

  $\begin{array}{llllllll}x\hfill & 700\hfill & 400\hfill & 1000\hfill & 800\hfill & 1200\hfill & 550\hfill & 300\hfill \\ y\hfill & 1100\hfill & 1500\hfill & 400\hfill & 600\hfill & 1000\hfill & 500\hfill & 250\hfill \end{array}$

Graph:

  

Interpretation: As the points are scattered throughout, slope is neither negative nor positive. There is no correlation between the data values and a rough estimate can be made stating that the correlation coefficient is near about $0$ . One variable is not causing change in the other; $\therefore$ it is not a causal relationship.

Thus the correlation coefficient is near about $0$ , and this is not a causal relationship.