Are Influential Points Always Outliers?

III. All outliers are influential data points.

What is the difference between an outlier and an influential point is an influential point necessarily an outlier?

An outlier is a data point that diverges from an overall pattern in a sample. ... An influential point is any point that has a large effect on the slope of a regression line fitting the data. They are generally extreme values.

Is an influential observation an outlier?

An outlier can either be influential or non-influential. If the outlier is an influential observation, then it has a big impact on the correlation coefficient, r, and on the least squares regression line. ... Notice how the regression line is affected much more by the outlier when there are only a few data points.