Tag Archives: correlation coefficient

Regression Fantasies

Common Reasons for Doubting a Regression Model Finding a model that fits a set of data is one of the most common goals in data analysis. Least squares regression is the most commonly used tool for achieving this goal. It’s … Continue reading

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How to Tell if Correlation Implies Causation

You’ve probably heard the admonition: Correlation Does Not Imply Causation. Everyone agrees that correlation is not the same as causation. However, those two words — correlation and causation — have generated quite a bit of discussion. Why Causality Matters No … Continue reading

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Why You Don’t Always Get the Correlation You Expect

If you’ve ever taken a statistics class on correlation, you’ve probably come to expect that a large value for a correlation coefficient, either positive or negative, means that there is a noteworthy relationship between two phenomena. This is not always … Continue reading

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O.U..T…L….I……E……..R………………..S

Datasets may contain values that is far greater (or less) than, or doesn’t display the same characteristics as the other values. If the influential observation is not representative of the population being sampled, it is called an outlier. Deciding what to do with outliers can be a challenge for data analysts. Continue reading

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Aphorisms for Data Analysts

An aphorism is a pithy saying that reveals some astute observation or popular notion, whether true or fictitious. “Lies, damn lies, and statistics” you’ve undoubtedly heard. If you’ve taken Stats 101, you probably know that “correlation doesn’t imply causation.” Here … Continue reading

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Grasping at Flaws

Even if you’re not a statistician, you may one day find yourself in the position of reviewing a statistical analysis that was done by someone else. It may be an associate, someone who works for you, or even a competitor. … Continue reading

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Secrets of Good Correlations

If you’ve ever seen a correlation coefficient, you’ve probably looked at the number and wondered, is that good? Is a correlation of -0.73 good but not a correlation of +0.58? Just what is a good correlation and what makes a … Continue reading

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Fifty Ways to Fix your Data

Fifty Ways to Fix your Data (Sing to the tune of “Fifty Ways to Leave Your Lover” by Paul Simon) The problem is all about your scales, she said to me The R-squares will be better if you’ve matched ’em … Continue reading

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The Right Tool for the Job

Statistics are like power tools. If you know how to use them, they are incredibly valuable and fun to use. They help you do your job better, more thoroughly, and more quickly. But if you are careless, they can cause … Continue reading

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30 Samples. Standard, Suggestion, or Superstition?

If you’ve ever taken any applied statistics courses in college, you may have been exposed to the mystique of 30 samples. Too many times I’ve heard statistician do-it-yourselfers tell me that “you need 30 samples for statistical significance.” Maybe that’s … Continue reading

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