Math Problem Statement

A researcher found a study relating the value of a car, y, to the age of the car, x. When researchers looked at the association of x and y, they found that the coefficient of determination was r squared equals 0.158.

Select a conclusion that the researcher can make from this data.

A.) About 16% of the variation in the value of the car is explained by a linear relationship with the age of the car.

B.) The correlation coefficient, r, is 0.842.

C.) The correlation coefficient, r, is 0.025.

D.) About 40% of the variation in the age of the car is explained by a linear relationship with the value of the car.

Solution

The coefficient of determination, r2r^2, represents the proportion of the variance in the dependent variable yy (the value of the car) that can be explained by the independent variable xx (the age of the car) through a linear relationship. In this case, r2=0.158r^2 = 0.158, which means about 15.8% (or approximately 16%) of the variation in the value of the car is explained by the car's age.

Correct answer:

A.) About 16% of the variation in the value of the car is explained by a linear relationship with the age of the car.

Explanation of why the other answers are incorrect:

  • B.) The correlation coefficient rr is the square root of r2r^2, so r=0.1580.398r = \sqrt{0.158} \approx 0.398, not 0.842.
  • C.) Similarly, rr is approximately 0.398, not 0.025.
  • D.) r2=0.158r^2 = 0.158 relates to the variation in value of the car explained by its age, not the other way around.

Would you like more details on how to interpret rr and r2r^2?

Related Questions:

  1. How do we calculate the correlation coefficient rr from r2r^2?
  2. Can the coefficient of determination ever be negative?
  3. What does a correlation coefficient rr close to 0 imply?
  4. How does the value of r2r^2 change as the strength of a linear relationship increases?
  5. Can the coefficient of determination r2r^2 be applied to non-linear relationships?

Tip: The coefficient of determination r2r^2 gives insight into how well the regression line fits the data, with higher values indicating a better fit.

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Math Problem Analysis

Mathematical Concepts

Statistics
Linear Regression
Coefficient of Determination

Formulas

r^2 = 0.158
r = sqrt(r^2)

Theorems

Coefficient of Determination

Suitable Grade Level

Grades 10-12