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Scatter plots, correlation, and regression

Scatter plots, correlation, and regression

From the course: Lean Six Sigma: Analyze, Improve, and Control Tools

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Scatter plots, correlation, and regression

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- Is the amount of coffee consumed at breakfast related to morning test scores? Is there a relationship between the price of gas and the price of apples? In other words, is there a correlation? In Lean Six Sigma projects, we are interested in seeing and analyzing how potential Xs impact Y. Is there a relationship between X and Y and if there is, is it a statistically significant relationship? That's when a correlation hypothesis test is needed. When there is a relationship between two variables, we say there is correlation. The strength of the relationship is quantified by the correlation coefficient r. It can range from minus one to plus one and if there is no correlation, the coefficient is zero or close to zero. If one variable increases as the other increases, the correlation coefficient will be positive with a maximum positive value of plus one. If one variable decreases as the other increases, the coefficient will be negative. The maximum possible negative correlation is minus…

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