Correlation Coefficient and Linear Regression Review

A department store has several retail outlets across the state. Each store has a different number of employees, and consequently produces varying amounts of annual sales. Which equation is the regression equation for this situation?

• y = 20x

• y = 21x

• y = 21.4x - 10.1

• y = 21.4x - 11.3

What kind of correlation?

• Positive

• Negative

• No

A value of r close to _______ indicates that there is either no linear relationship between the variables or a weak one.

• -1

• 0

• 1

• -0.9

If two variables have a negative linear correlation, then that means as x increases, y _______

• Increases

• Decreases

• Stays the same

• Cannot be determined

• 
• 
• 
• 

• 
• 
• 
• 

Which of the following statements about the correlation coefficient is true?

• The correlation coefficient and the slope of the regression line have opposite signs

• A correlation coefficient of 1 indicates a perfect causal relationship between the variables

• Correlations of 0.87 and -0.87 indicate the same strength of correlation between the variables

• A correlation of 0 means the shape of the scatter plot is quadratic

• 17.1

• 18.1

• 19.1

• 20.1

• -0.755

• -0.325

• 0.325

• 0.755

Determine if the statement is true or false. If a statement is false, correct it so that it will be true. A correlation coefficient of -0.68 would mean that as the value of x increases, the value of y increases.

• True

• False, A correlation coefficient of -0.68 would mean that as the value of x increases, the value of y decreases.

• False, A correlation coefficient of -0.68 would mean that 68% of the variation of y is accounted for by the linear model with x.