A model performs well on its training data but much worse on separate validation data. Which issue is this pattern most likely to indicate?
8 Overfitting and Generalization Online Quiz Questions
Use this free practice quiz with 20 questions to review 8 Overfitting and Generalization, test your knowledge, and prepare for your next test or exam.
A model performs poorly on both its training data and validation data. What modeling problem does this pattern most likely indicate?
Generalization describes a model's ability to make accurate predictions on previously unseen data.
- A
True
- B
False
A very high-degree polynomial passes through every training point, including unusual sales, but predicts prices poorly for other houses. What is the best explanation?
- A
It is underfitting because it cannot match the training points.
- B
It is guaranteed to generalize well because its training error is low.
- C
It may be overfitting by capturing noise or accidental details in the training data.
- D
It is experiencing data leakage because the polynomial has many terms.
A model is overfitting. Which actions could help reduce its effective complexity or prevent it from continuing to fit training-data quirks? Select all that apply.
- A
Limit a decision tree's depth.
- B
Use regularization to discourage overly complex parameter values.
- C
Increase the model's flexibility so it can fit every training example more closely.
- D
Use early stopping when validation performance stops improving.
Use to compare models or tune settings, and keep the test set for final evaluation.
What problem can occur if you perform preprocessing or feature selection before splitting a dataset into training, validation, and test sets? Enter the established term.
Which practices help prevent data leakage during preprocessing? Select all that apply.
- A
Split the data before preprocessing or feature selection.
- B
Fit scaling or imputation on training data, then apply the learned transformation to validation and test data.
- C
Fit preprocessing steps on the full dataset before creating the training and validation splits.
- D
Use pipelines to keep preprocessing steps within the correct data split.
In k-fold cross-validation, the model trains on all but one fold and validates on the remaining fold, repeating until every fold has served as validation data.
- A
True
- B
False
A model appears to underfit because strong regularization is preventing it from learning useful patterns. Which change is most appropriate?
- A
Increase regularization further.
- B
Reduce excessive regularization.
- C
Limit decision-tree depth even more.
- D
Stop training earlier.
In k-fold cross-validation, each fold serves once as the while the model trains on all the other folds.
Which tools can help reveal patterns in model performance as training or model settings vary?
- A
A final test score alone, without comparing performance patterns.
- B
A list of training examples in their original order.
- C
Learning curves and validation curves.
- D
The number of parameters, considered without any performance measurements.
When comparing model performance, lower mean squared error is better, while higher accuracy is better.
- A
True
- B
False
Explain how validation and test data should be used during model development, and why repeatedly choosing settings based on test performance can undermine the final evaluation.
What machine-learning term describes the ability to make accurate predictions on previously unseen data?
A deep decision tree performs well on training data but much worse on validation data. Which change most directly addresses the likely problem?
- A
Increase the tree depth so it can fit the training data more closely.
- B
Limit the tree depth to reduce the model's effective complexity.
- C
Choose settings by repeatedly checking the test score.
- D
Fit preprocessing steps using the validation data.
A model's training and validation performance are both poor. The model is known to be too simple, and training has converged. Which change is most appropriate?
- A
Use a simpler model and increase regularization.
- B
Reduce the amount of training data.
- C
Try a more suitable model or add useful features.
- D
Choose model settings using only the test score.
Name one type of curve that can help reveal overfitting or underfitting patterns.
A team discovers that its training examples do not resemble the situations in which its predictions will be used. What should it prioritize to support generalization?
- A
Check that the training examples are representative of the situations where predictions will be used.
- B
Use only examples that are easy for the current model to predict.
- C
Select training examples based on the test score.
- D
Make the model more complex regardless of the data.
When dividing data for model development, which practice correctly distinguishes validation data from the test set?
- A
Use the test set to tune settings, then use validation data for the final evaluation.
- B
Use validation data to compare models or tune settings, and reserve the test set for final evaluation.
- C
Use validation data to fit the model and training data only for the final evaluation.
- D
Use training data for tuning and repeatedly check the test set after every change.