Correlation and Linear Regression: Pearson Correlation Coefficient
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Questions and Answers

What is the range of the Pearson correlation coefficient?

  • -2 to 0
  • 0 to 2
  • -1 to 1 (correct)
  • 1 to 3
  • If points fall on a straight line with a negative slope, what value would the correlation coefficient have?

  • 1
  • 0
  • -1 (correct)
  • 2
  • What does a correlation of 0 indicate?

  • Strong linear relationship
  • Perfect negative correlation
  • Points are not linearly related (correct)
  • Perfect positive correlation
  • How does changing the units of measurement affect the correlation coefficient?

    <p>It does not change</p> Signup and view all the answers

    What is the sample covariance defined as with respect to bivariate data?

    <p>(xi - x)(yi - y)</p> Signup and view all the answers

    In an elementary school where shoe size and reading level are measured, what kind of correlation is observed?

    <p>Positive correlation</p> Signup and view all the answers

    What is Age referred to as in the context of the text?

    <p>Lurking variable</p> Signup and view all the answers

    Why should we only consider linear relationships in the context of linear regression?

    <p>Variables with nonlinear relationships can sometimes be transformed to be linear.</p> Signup and view all the answers

    What does a lurking variable cause in the correlation between two variables?

    <p>It causes a spurious correlation.</p> Signup and view all the answers

    What is the objective of linear regression according to the text?

    <p>To fit a straight line to the data.</p> Signup and view all the answers

    Which variable is referred to as the response in linear regression?

    <p>Output variable</p> Signup and view all the answers

    Why are linear relationships preferred over nonlinear ones in certain cases?

    <p>Nonlinear relationships can sometimes be closely approximated by linear relationships.</p> Signup and view all the answers

    What do the constants β0 and β1 represent in the equation of a straight line y = β1x + β0?

    <p>β0 is the y-intercept and β1 is the slope</p> Signup and view all the answers

    Why is it challenging to determine the 'best-fitting' line using visual inspection?

    <p>Different people will perceive lines differently</p> Signup and view all the answers

    What does the least squares line minimize in the context of regression analysis?

    <p>Sum of squared deviations from the data</p> Signup and view all the answers

    How are the estimated values of β0 and β1 calculated using the least square method?

    <p>By minimizing the sum of squared errors</p> Signup and view all the answers

    What does yb represent in the context of a regression line with equation y = βb1x + βb0?

    <p>Predicted value given an x-variable</p> Signup and view all the answers

    Why do we use scatter diagrams before estimating β0 and β1 for regression analysis?

    <p>To determine if a linear relationship exists between variables</p> Signup and view all the answers

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