A held-out test set can estimate a model’s performance on future data when the test examples are sufficiently similar to the data the model will encounter in use.
8 Generalization and Overfitting Online Quiz Questions
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A model has poor performance on both its training data and its validation data. Which interpretation best fits this score pattern?
- A
Overfitting
- B
Underfitting
- C
A useful fit with a modest gap
A model fits its training examples closely, including random noise that does not recur, and performs substantially worse on new examples. This is called .
Which actions are suggested ways to address a model that is overfitting? Select all that apply.
- A
Reduce the model’s complexity
- B
Remove unhelpful features
- C
Make the model more expressive
- D
Use regularization
Which regularization method discourages excessively large model weights?
If a preprocessing step is learned using the full dataset before it is split into training and evaluation data, information can improperly cross the split. This problem is called .
A model performs well on a held-out test set, but the distribution of real-world examples later changes. What is the most appropriate conclusion?
- A
The original test score guarantees the model will perform just as well.
- B
The model must be overfitting because its test score was high.
- C
Performance may change because the real-world data distribution has changed.
- D
The training data should be used as the final evaluation set.
Adding more training examples is guaranteed to improve performance, even if the new examples do not represent the cases the model must handle.
- A
True
- B
False
Which practices help preserve a meaningful final evaluation while comparing models and settings? Select all that apply.
- A
Compare candidate models using cross-validation.
- B
Choose the model based on repeated adjustments to its test-set results.
- C
Keep a separate test set for the final evaluation.
- D
Use the test set to fit each candidate model.
What can learning curves and validation curves help reveal?
- A
They guarantee that the validation data match future real-world data.
- B
They replace the need for a separate final test set.
- C
They can help reveal underfitting or overfitting as training-set size or model settings change.
- D
They improve performance by automatically removing noisy examples.
Which sequence best describes a practical workflow for improving model performance?
- A
Establish a simple baseline, inspect training and validation performance, make a targeted change, and compare using the same validation method.
- B
Start with the most complex model and select it using the test set.
- C
Change several parts of the model at once and compare scores from different validation methods.
- D
Skip baseline measurements and evaluate only on training data.
A model performs poorly on both its training data and validation data. Explain the likely diagnosis and describe suitable next steps for improving it.
What is the term for a model’s ability to make useful predictions on examples it did not train on?
A model’s validation score looks strong, but the metric may not reflect what matters for the task. What should you do?
- A
Keep the metric because it is commonly used, regardless of the task.
- B
Check whether the metric reflects the goal of the task.
- C
Use training performance alone to decide whether the metric is suitable.
- D
Choose whichever metric gives the model the highest score.
A model scores very well on its training set but substantially worse on a representative validation set. Which interpretation is most likely?
- A
Underfitting
- B
Overfitting
- C
Useful fit with a modest gap
- D
Data leakage
A straight-line model performs poorly on both training and validation data, but the underlying relationship is strongly curved. Which change most directly addresses the likely problem?
- A
Add more training examples without checking what they represent
- B
Increase regularization to penalize complexity more strongly
- C
Try a more expressive model that can capture curvature
- D
Stop training as soon as validation performance stops improving
What resampling method is recommended for comparing candidate models and settings?
When can performance on a held-out test set serve as a useful estimate of a model's performance on future data?
- A
The test examples are relevant to the intended use and sufficiently similar to future data
- B
The model achieves excellent training performance, regardless of the test examples
- C
The test set is repeatedly used to choose model settings
- D
The test set is larger than the training set
True or false: After selecting a model using validation results, it is good practice to keep a separate test set for final evaluation.
- A
True
- B
False
What technique penalizes model complexity, with L2 being an example that discourages excessively large weights?