Chapter 4.1, Problem 4.18E

(a)

To determine

To match the r’s given in the question that best describes the scatterplot.

Answer to Problem 4.18E

  $r=0.9$

Explanation of Solution

The scatterplot slopes upwards, thus r has to be positive. The points are close together thus |r| has to be $1$ :

  $r=0.9$

(b)

To determine

To match the r’s given in the question that best describes the scatterplot.

Answer to Problem 4.18E

  $r=-0.3$

Explanation of Solution

The scatterplot slopes downwards, thus r has to be negative. The points are very far apart thus |r| has to be close to zero:

  $r=-0.3$

(c)

To determine

To match the r’s given in the question that best describes the scatterplot.

Answer to Problem 4.18E

  $r=0.7$

Explanation of Solution

The scatterplot slopes upwards, thus r has to be positive. The points are relatively close together thus |r| has to be close to between $0.5\text{ and }1$ :

  $r=0.7$

(d)

To determine

To match the r’s given in the question that best describes the scatterplot.

Answer to Problem 4.18E

  $r=0$

Explanation of Solution

The scatterplot shows no pattern thus:

  $r=0$

(e)

To determine

To match the r’s given in the question that best describes the scatterplot.

Answer to Problem 4.18E

  $r=-0.9$

Explanation of Solution

The scatterplot slopes downwards, thus r has to be negative. The points are very far apart thus |r| has to be close to $1$ :

  $r=-0.9$