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Ch. 9 - Correlation and Regression
Larson - Elementary Statistics: Picturing the World 8th Edition
Larson8th EditionElementary Statistics: Picturing the WorldISBN: 9780137493470당신이 사용하는 게 아니라요?교과서 변경
9장, 문제 9.3.5

What is the coefficient of determination for two variables that have perfect positive linear correlation or perfect negative linear correlation? Interpret your answer.

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Recall that the coefficient of determination, denoted as R², is the square of the correlation coefficient r. It measures the proportion of variance in one variable that is predictable from the other variable.
Understand that a perfect positive linear correlation means the correlation coefficient r = +1, and a perfect negative linear correlation means r = -1.
Calculate the coefficient of determination by squaring the correlation coefficient: R² = (r)². For both r = +1 and r = -1, this will be 1² = 1.
Interpret the coefficient of determination value of 1 as indicating that 100% of the variance in one variable is explained by the variance in the other variable, meaning a perfect linear relationship.
Conclude that whether the correlation is perfectly positive or perfectly negative, the coefficient of determination is 1, showing a perfect linear association in terms of explained variance.

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주요 개념

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Coefficient of Determination (R²)

The coefficient of determination, denoted as R², measures the proportion of variance in the dependent variable that is predictable from the independent variable. It ranges from 0 to 1, where 1 indicates perfect prediction and 0 indicates no predictive power.
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가이드 코스
06:14
Coefficient of Determination

Correlation Coefficient (r)

The correlation coefficient, r, quantifies the strength and direction of a linear relationship between two variables. It ranges from -1 (perfect negative linear correlation) to +1 (perfect positive linear correlation), with 0 indicating no linear correlation.
추천 영상:
가이드 코스
05:43
Correlation Coefficient

Relationship Between R² and r

The coefficient of determination R² is the square of the correlation coefficient r. For perfect positive (r = +1) or perfect negative (r = -1) linear correlation, R² equals 1, meaning the model explains 100% of the variance in the data regardless of the correlation's direction.
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가이드 코스
03:50
Probabilities Between Two Values