MLS-C01 Modeling Practice Question
A data scientist is training a random forest model for a binary classification task. The dataset has 100,000 samples and 500 features. The model is overfitting. Which TWO actions are MOST likely to reduce overfitting?
⚠ Common exam trap
AWS often tests the misconception that adding more trees always reduces overfitting, but the trap here is that without controlling tree complexity (depth or split criteria), more trees can still produce an overfit ensemble, especially when individual trees are allowed to grow unchecked.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reduce the maximum depth of each tree
Reducing the maximum depth of each tree limits the complexity of individual trees, preventing them from memorizing noise and specific patterns in the training data. This is a standard regularization technique for random forests that directly combats overfitting by controlling the variance of the model.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the number of trees in the forest
Why it's wrong here
More trees usually improve generalization but do not directly reduce overfitting; it can actually increase if trees are overfit.
- ✓
Reduce the maximum depth of each tree
Why this is correct
Shorter trees are simpler and less likely to overfit.
- ✗
Increase the number of features considered at each split
Why it's wrong here
This can increase tree diversity but may not reduce overfitting; often it helps generalization.
- ✗
Use all features for each tree
Why it's wrong here
Using all features reduces tree diversity and may increase overfitting.
- ✓
Increase the minimum number of samples required to split an internal node
Why this is correct
Higher min samples split prevents learning from noise, reducing overfitting.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MLS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the MLS-C01 exam.