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91Ó°ÊÓ

Use the linear correlation coefficient given to determine the coefficient of determination, \(R^{2} .\) Interpret each \(R^{2}\) (a) \(r=-0.32\) (b) \(r=0.13\) (c) \(r=0.40\) (d) \(r=0.93\)

Short Answer

Expert verified
For r=-0.32, R²=0.1024. For r=0.13, R²=0.0169. For r=0.40, R²=0.16. For r=0.93, R²=0.8649.

Step by step solution

01

- Understanding the Relationship Between r and R²

The coefficient of determination, denoted as \(R^2\), is calculated by squaring the linear correlation coefficient, denoted as \(r\). It explains the proportion of the variance in the dependent variable that is predictable from the independent variable.
02

- Calculate R² for r = -0.32

To find \(R^2\) for \(r = -0.32\), square the value of \(r\): \[R^2 = (-0.32)^2 = 0.1024\] Thus, \(R^2 = 0.1024\). This means approximately 10.24% of the variance in the dependent variable is predictable from the independent variable.
03

- Calculate R² for r = 0.13

To find \(R^2\) for \(r = 0.13\), square the value of \(r\): \[R^2 = (0.13)^2 = 0.0169\] Thus, \(R^2 = 0.0169\). This means approximately 1.69% of the variance in the dependent variable is predictable from the independent variable.
04

- Calculate R² for r = 0.40

To find \(R^2\) for \(r = 0.40\), square the value of \(r\): \[R^2 = (0.40)^2 = 0.16\] Thus, \(R^2 = 0.16\). This means approximately 16% of the variance in the dependent variable is predictable from the independent variable.
05

- Calculate R² for r = 0.93

To find \(R^2\) for \(r = 0.93\), square the value of \(r\): \[R^2 = (0.93)^2 = 0.8649\] Thus, \(R^2 = 0.8649\). This means approximately 86.49% of the variance in the dependent variable is predictable from the independent variable.
06

- Summarize Results

For \(r = -0.32\), \(R^2 = 0.1024\) which means 10.24% predictability. For \(r = 0.13\), \(R^2 = 0.0169\) which means 1.69% predictability. For \(r = 0.40\), \(R^2 = 0.16\) which means 16% predictability. For \(r = 0.93\), \(R^2 = 0.8649\) which means 86.49% predictability.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

linear correlation coefficient
The linear correlation coefficient, also known as Pearson's correlation coefficient, is a measure of the strength and direction of a linear relationship between two variables. It's denoted by the symbol \( r \). The value of \( r \) ranges from -1 to 1. When \( r \) is close to 1, it indicates a strong positive linear relationship. Conversely, when \( r \) is close to -1, it shows a strong negative linear relationship. An \( r \) value near 0 suggests no linear correlation between the variables.
variance
Variance is a statistical concept that measures the dispersion or spread of a set of numbers. In simpler terms, it shows how much the numbers in a dataset differ from the mean of the dataset. Higher variance indicates that the numbers are more spread out from the mean, while lower variance indicates that the numbers are close to the mean.
Variance is a crucial concept in calculating the coefficient of determination because \( R^2 \) explains how much of the variance in the dependent variable can be predicted by the independent variable.
predictability
Predictability in statistics refers to the extent to which we can predict the value of one variable based on the value of another variable. The coefficient of determination, \( R^2 \), quantifies this predictability.
For example, if \( R^2 = 0.8649 \), it means 86.49% of the variance in the dependent variable is predictable from the independent variable, thus indicating a high level of predictability. Lower \( R^2 \) values indicate lower predictability. Understanding how much variance is predictable helps analysts make informed decisions based on data-driven insights.

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