The scatterplot below shows the relationship between two random variables X and Y. 9 5 4 3 2 0 8 O 2 X 8 O O 00 3 (a) Is the correlation a good metric for describing the relationship between X and Y for these data? Why or why not? (b) Regardless of your answer to part (a), suppose you calculated the sample correlation between X and Y and found that r = -0.15. Explain in one sentence what this means. (c) If, as noted in (b), r = -0.15 then what is the value of the correlation between 2X and 5 Y?

MATLAB: An Introduction with Applications
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The scatterplot below shows the relationship between two random variables X and Y.

 

  • Is the correlation a good metric for describing the relationship between X and Y for these data? Why or why not?

 

  • Regardless of your answer to part (a), suppose you calculated the sample correlation between X and Y and found that r = -0.15. Explain in one sentence what this means.

 

  • If, as noted in (b), r = -0.15 then what is the value of the correlation between 2X and 5Y?

 

  • Based on (b) draw your best approximation to the least squares regression line that fits the data above. Also, make a rough sketch of the corresponding residual plot.  (The sketches do not have to be beautiful but they have to covey the correct information.) 
**Scatterplot Analysis and Correlation**

The scatterplot below illustrates the relationship between two random variables \( X \) and \( Y \).

### Scatterplot Explanation
- **X-Axis:** The variable \( X \) is represented along the horizontal axis.
- **Y-Axis:** The variable \( Y \) is depicted on the vertical axis.
- **Data Points:** Individual data points are plotted on the graph, showing the values of \( Y \) corresponding to each \( X \).

### Questions

**(a)** Is the correlation a good metric for describing the relationship between \( X \) and \( Y \) for these data? Why or why not?

- Consider whether the relationship appears linear or if there are other factors at play that might make correlation an inadequate measure.

**(b)** Regardless of your answer to part (a), suppose you calculated the sample correlation between \( X \) and \( Y \) and found \( r = -0.15 \). Explain in one sentence what this means.

- A correlation \( r = -0.15 \) indicates a weak negative linear relationship between the variables \( X \) and \( Y \).

**(c)** If, as noted in (b), \( r = -0.15 \) then what is the value of the correlation between \( 2X \) and \( 5Y \)?

- The correlation remains unchanged when scaling the variables; thus, the correlation between \( 2X \) and \( 5Y \) is also \( -0.15 \).
Transcribed Image Text:**Scatterplot Analysis and Correlation** The scatterplot below illustrates the relationship between two random variables \( X \) and \( Y \). ### Scatterplot Explanation - **X-Axis:** The variable \( X \) is represented along the horizontal axis. - **Y-Axis:** The variable \( Y \) is depicted on the vertical axis. - **Data Points:** Individual data points are plotted on the graph, showing the values of \( Y \) corresponding to each \( X \). ### Questions **(a)** Is the correlation a good metric for describing the relationship between \( X \) and \( Y \) for these data? Why or why not? - Consider whether the relationship appears linear or if there are other factors at play that might make correlation an inadequate measure. **(b)** Regardless of your answer to part (a), suppose you calculated the sample correlation between \( X \) and \( Y \) and found \( r = -0.15 \). Explain in one sentence what this means. - A correlation \( r = -0.15 \) indicates a weak negative linear relationship between the variables \( X \) and \( Y \). **(c)** If, as noted in (b), \( r = -0.15 \) then what is the value of the correlation between \( 2X \) and \( 5Y \)? - The correlation remains unchanged when scaling the variables; thus, the correlation between \( 2X \) and \( 5Y \) is also \( -0.15 \).
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