Databricks-Machine-Learning-Associate Exam Questions and Answers (Page: 3)

QUESTION: 11

What is the name of the method that transforms categorical features into a series of binary indicator feature variables?

Leave-one-out encoding
Target encoding
One-hot encoding
Categorical
String indexing

Answer(s): C

Explanation:

The method that transforms categorical features into a series of binary indicator variables is known as one-hot encoding. This technique converts each categorical value into a new binary column, which is essential for models that require numerical input. One-hot encoding is widely used because it helps to handle categorical data without introducing a false ordinal relationship among categories.

Reference:

Feature Engineering Techniques (One-Hot Encoding).

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QUESTION: 12

A data scientist wants to parallelize the training of trees in a gradient boosted tree to speed up the training process. A colleague suggests that parallelizing a boosted tree algorithm can be difficult.
Which of the following describes why?

Gradient boosting is not a linear algebra-based algorithm which is required for parallelization
Gradient boosting requires access to all data at once which cannot happen during parallelization.
Gradient boosting calculates gradients in evaluation metrics using all cores which prevents parallelization.
Gradient boosting is an iterative algorithm that requires information from the previous iteration to perform the next step.

Answer(s): D

Explanation:

Gradient boosting is fundamentally an iterative algorithm where each new tree is built based on the errors of the previous ones. This sequential dependency makes it difficult to parallelize the training of trees in gradient boosting, as each step relies on the results from the preceding step. Parallelization in this context would undermine the core methodology of the algorithm, which depends on sequentially improving the model's performance with each iteration.

Reference:

Machine Learning Algorithms (Challenges with Parallelizing Gradient Boosting).

Gradient boosting is an ensemble learning technique that builds models in a sequential manner. Each new model corrects the errors made by the previous ones. This sequential dependency means that each iteration requires the results of the previous iteration to make corrections. Here is a step-by- step explanation of why this makes parallelization challenging:
Sequential Nature: Gradient boosting builds one tree at a time. Each tree is trained to correct the residual errors of the previous trees. This requires the model to complete one iteration before starting the next.
Dependence on Previous Iterations: The gradient calculation at each step depends on the predictions made by the previous models. Therefore, the model must wait until the previous tree has been fully trained and evaluated before starting to train the next tree. Difficulty in Parallelization: Because of this dependency, it is challenging to parallelize the training process. Unlike algorithms that process data independently in each step (e.g., random forests),

gradient boosting cannot easily distribute the work across multiple processors or cores for simultaneous execution.
This iterative and dependent nature of the gradient boosting process makes it difficult to parallelize effectively.
Reference
Gradient Boosting Machine Learning Algorithm
Understanding Gradient Boosting Machines

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QUESTION: 13

A data scientist wants to efficiently tune the hyperparameters of a scikit-learn model. They elect to use the Hyperopt library's fmin operation to facilitate this process. Unfortunately, the final model is not very accurate. The data scientist suspects that there is an issue with the objective_function being passed as an argument to fmin.

They use the following code block to create the objective_function:

Which of the following changes does the data scientist need to make to their objective_function in order to produce a more accurate model?

Add test set validation process
Add a random_state argument to the RandomForestRegressor operation
Remove the mean operation that is wrapping the cross_val_score operation
Replace the r2 return value with -r2
Replace the fmin operation with the fmax operation

Answer(s): D

Explanation:

When using the Hyperopt library with fmin, the goal is to find the minimum of the objective function. Since you are using cross_val_score to calculate the R2 score which is a measure of the proportion of the variance for a dependent variable that's explained by an independent variable(s) in a regression model, higher values are better. However, fmin seeks to minimize the objective function, so to align with fmin's goal, you should return the negative of the R2 score (-r2). This way, by minimizing the negative R2, fmin is effectively maximizing the R2 score, which can lead to a more accurate model.
Reference
Hyperopt Documentation: http://hyperopt.github.io/hyperopt/ Scikit-Learn documentation on model evaluation: https://scikit- learn.org/stable/modules/model_evaluation.html

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QUESTION: 14

A data scientist is attempting to tune a logistic regression model logistic using scikit-learn. They want to specify a search space for two hyperparameters and let the tuning process randomly select values for each evaluation.

They attempt to run the following code block, but it does not accomplish the desired task:

Which of the following changes can the data scientist make to accomplish the task?

Replace the GridSearchCV operation with RandomizedSearchCV
Replace the GridSearchCV operation with cross_validate
Replace the GridSearchCV operation with ParameterGrid
Replace the random_state=0 argument with random_state=1
Replace the penalty= ['12', '11'] argument with penalty=uniform ('12', '11')

Answer(s): A

Explanation:

The user wants to specify a search space for hyperparameters and let the tuning process randomly select values. GridSearchCV systematically tries every combination of the provided hyperparameter values, which can be computationally expensive and time-consuming. RandomizedSearchCV, on the other hand, samples hyperparameters from a distribution for a fixed number of iterations. This approach is usually faster and still can find very good parameters, especially when the search space is large or includes distributions.
Reference
Scikit-Learn documentation on hyperparameter tuning: https://scikit- learn.org/stable/modules/grid_search.html#randomized-parameter-optimization

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QUESTION: 15

Which of the following tools can be used to parallelize the hyperparameter tuning process for single-

node machine learning models using a Spark cluster?

MLflow Experiment Tracking
Spark ML
Autoscaling clusters
Autoscaling clusters
Delta Lake

Answer(s): B

Explanation:

Spark ML (part of Apache Spark's MLlib) is designed to handle machine learning tasks across multiple nodes in a cluster, effectively parallelizing tasks like hyperparameter tuning. It supports various machine learning algorithms that can be optimized over a Spark cluster, making it suitable for parallelizing hyperparameter tuning for single-node machine learning models when they are adapted to run on Spark.
Reference
Apache Spark MLlib Guide: https://spark.apache.org/docs/latest/ml-guide.html

Spark ML is a library within Apache Spark designed for scalable machine learning. It provides tools to handle large-scale machine learning tasks, including parallelizing the hyperparameter tuning process for single-node machine learning models using a Spark cluster. Here's a detailed explanation of how Spark ML can be used:
Hyperparameter Tuning with CrossValidator: Spark ML includes the CrossValidator and TrainValidationSplit classes, which are used for hyperparameter tuning. These classes can evaluate multiple sets of hyperparameters in parallel using a Spark cluster. from pyspark.ml.tuning import CrossValidator, ParamGridBuilder from pyspark.ml.evaluation import BinaryClassificationEvaluator

# Define the model model = ...

# Create a parameter grid paramGrid = ParamGridBuilder() \
.addGrid(model.hyperparam1, [value1, value2]) \
.addGrid(model.hyperparam2, [value3, value4]) \

.build()

# Define the evaluator evaluator = BinaryClassificationEvaluator()

# Define the CrossValidator crossval = CrossValidator(estimator=model,
estimatorParamMaps=paramGrid,
evaluator=evaluator,
numFolds=3)

Parallel Execution: Spark distributes the tasks of training models with different hyperparameters across the cluster's nodes. Each node processes a subset of the parameter grid, which allows multiple models to be trained simultaneously.
Scalability: Spark ML leverages the distributed computing capabilities of Spark. This allows for efficient processing of large datasets and training of models across many nodes, which speeds up the hyperparameter tuning process significantly compared to single-node computations.
Reference
Apache Spark MLlib Documentation
Hyperparameter Tuning in Spark ML

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Databricks Databricks-Machine-Learning-Associate Exam (page: 3) Databricks Certified Machine Learning Associate Updated on: 02-Jan-2026

QUESTION: 11

Explanation:

Reference:

QUESTION: 12

Explanation:

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QUESTION: 13

Explanation:

QUESTION: 14

Explanation:

QUESTION: 15

Explanation:

Databricks Databricks-Machine-Learning-Associate Exam (page: 3)
Databricks Certified Machine Learning Associate
Updated on: 02-Jan-2026