18.4 - Pearson's Correlation Coefficient Flashcards
What correlation is Calculating and interpreting Pearson's correlation coefficient
What is correlation?
Relationship between two variables
What is positive correlation?
Both variables increase or decrease together
What is negative correlation?
One variable increases as the other decreases
What is non-existent correlation?
No clear relationship
What does a correlation coefficient of 1 indicate?
Perfect positive linear correlation
What is Pearson’s correlation coefficient (r)?
Assesses strength and direction of linear relationship
What is the formula for Pearson’s correlation coefficient?
r = Σ[(x-x̄)(y-ȳ)] / √[Σ(x-x̄)^2 * Σ(y-ȳ)^2]
What does Σ represent?
Sum of
What does x̄ represent?
Mean of x values
What does ȳ represent?
Mean of y values
What are the steps to calculate Pearson’s correlation coefficient?
Calculate means
How do you determine significance of the correlation?
Compare r value to critical value at 5% significance level
What are degrees of freedom for Pearson’s correlation coefficient?
n - 2
What does an r value near +1 indicate?
Strong positive correlation
What does an r value near -1 indicate?
Strong negative correlation
What does an r value around 0 indicate?
No correlation
