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Are fitted values the same as predicted values?
A fitted value is a statistical model’s prediction of the mean response value when you input the values of the predictors, factor levels, or components into the model. Fitted values are also called predicted values.
Does a residual plot show outliers?
A studentized residual is calculated by dividing the residual by an estimate of its standard deviation. Studentized residuals falling outside the red limits are potential outliers. This plot does not show any obvious violations of the model assumptions. We also do not see any obvious outliers or unusual observations.
What is a high residual outlier?
y-Outlier Point An observation is generally considered an outlier if the absolute value of the residual (RESI) is higher. For example, the data point # 6 has a very high residual compared to any other data points of the data set.
What is a large Studentized residual?
If an observation has a studentized residual that is larger than 3 (in absolute value) we can call it an outlier. [Recall from the previous section that some use the term “outlier” for an observation with a standardized residual that is larger than 3 in absolute value.
The first plot seems to indicate that the residuals and the fitted values are uncorrelated, as they should be in a homoscedastic linear model with normally distributed errors. Therefore, the second and third plots, which seem to indicate dependency between the residuals and the fitted values, suggest a different model.
How does an outlier show up on a residual plot?
Note that the residuals “fan out” from left to right rather than exhibiting a consistent spread around the residual = 0 line. The residual vs. fits plot suggests that the error variances are not equal. How does an outlier show up on a residuals vs. fits plot?
Are there any outliers in studentized residuals?
Studentized residuals falling outside the red limits are potential outliers. This plot does not show any obvious violations of the model assumptions. We also do not see any obvious outliers or unusual observations. Let’s take a closer look at the topic of outliers, and introduce some terminology.
How to interpret residuals vs.fitted values plot?
Below are those residual plots with the approximate mean and spread of points (limits that include most of the values) at each value of fitted (and hence of x) marked in – to a rough approximation indicating the conditional mean (red) and conditional mean ± (roughly!) twice the conditional standard deviation (purple):