COMPSCI C8 Lecture Notes - Lecture 31: Scatter Plot, Standard Deviation
14 Mar 2018
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Document Summary
Some errors are positive and some negative. To measure the rough size of the errors: square the error to eliminate cancellation, take the mean of the squared errors, take the square root to fix the units, root mean square error (rmse) One residual corresponding to each point (x, y) Residual = observed y regression estimate of y: observed y height of regression line at x, vertical difference between point and line. A scatter diagram of residuals: should look like an unassociated blob for linear relations, but still contains patterns for non-linear relations, used to check whether linear regression is appropriate. The mea of residuals is always 0, regardless of the original data.
