MLS-C01 Exploratory Data Analysis Practice Question
A data scientist is analyzing a dataset with 10,000 rows and 50 columns. The target variable is binary. Which technique is most appropriate for identifying the most important features for predicting the target?
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
✓
Train a Random Forest classifier and use feature_importances_
The most appropriate technique for identifying the most important features for predicting a binary target is to train a Random Forest classifier and use the built-in feature_importances_ attribute (Option C). Random Forest is a supervised ensemble method that provides a ranking of feature importance based on how much each feature reduces impurity (e.g., Gini impurity) across all trees. Option A (t-SNE) is a nonlinear dimensionality reduction technique primarily used for visualization in 2D/3D; it does not provide feature importance. Option B (K-means clustering) is an unsupervised clustering algorithm that does not use the target variable and cannot identify predictive features. Option D (PCA) is an unsupervised dimensionality reduction method that finds principal components maximizing variance, but these components are not directly interpretable as feature importance for a specific target variable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use t-SNE to reduce dimensionality and inspect clusters
Why it's wrong here
t-SNE is for visualization, not feature selection.
- ✗
Run K-means clustering and examine cluster centroids
Why it's wrong here
K-means is unsupervised and does not identify feature importance for prediction.
- ✓
Train a Random Forest classifier and use feature_importances_
Why this is correct
Random Forest provides feature importance scores based on impurity reduction.
- ✗
Apply PCA and select components with highest variance
Why it's wrong here
PCA does not consider the target variable.
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