Correlation and Slope Formulas:
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The correlation coefficient (r) measures the strength and direction of the linear relationship between two variables. The slope represents the rate of change between these variables in a linear regression model.
The calculator uses these formulas:
Where:
Explanation: The correlation coefficient shows how closely two variables move together, while the slope indicates how much y changes for a unit change in x.
Details: These statistics are fundamental in data analysis, helping to understand relationships between variables and make predictions.
Tips: Enter covariance and standard deviations for your variables. All values must be valid (standard deviations > 0).
Q1: What does the correlation coefficient value mean?
A: Values range from -1 (perfect negative correlation) to +1 (perfect positive correlation). 0 indicates no linear correlation.
Q2: How to interpret the slope?
A: The slope indicates how much the dependent variable (y) changes for each unit change in the independent variable (x).
Q3: What's the difference between correlation and slope?
A: Correlation measures the strength of relationship, while slope measures the rate of change. Correlation is unitless, slope has units of y/x.
Q4: What are common mistakes when interpreting these?
A: Confusing correlation with causation, ignoring non-linear relationships, and not considering the context of the data.
Q5: When should these calculations not be used?
A: When the relationship isn't linear, with outliers that strongly influence results, or with categorical data.