In probability theory and statistics, correlation, (often measured as a correlation coefficient) indicates the strength and direction of a linear relationship between two random variables
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The Pearson Product Moment Correlation (PMCC)also called the Pearson Correlationwas named after Karl Pearson, a British scientist and founder of the mathematical statistics discipline
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I don't know how Excel calculates the Rsquared for the model without intercept, but whatever it is doing, it doesn't sound like it can be usefully compared to the Rsquared with
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