AI-900 Practice Questions

According to the Microsoft Azure AI Fundamentals (AI-900) Official Study Guide and the Microsoft Learn module “Explore fundamental principles of machine learning,” a regression model is used when the goal is to predict a continuous numerical value based on historical data.

In this question, the task is to predict the sale price of auctioned items, which is a numeric output that can take on a wide range of values (for example, $50.25, $199.99, etc.). This makes it a regression problem because the output is continuous rather than categorical.

Regression models analyze the relationship between input features (such as item type, condition, age, bidding history, or demand) and a numerical target variable (the sale price). Common regression algorithms include linear regression, decision tree regression, and neural network regression. In Azure Machine Learning, these models are trained using labeled datasets containing known outcomes to learn patterns and make future predictions.

Let’s review the incorrect options:

Classification: Used to predict discrete categories or labels, such as “sold” vs. “unsold” or “low,” “medium,” “high.” It cannot output continuous numeric predictions.

Clustering: An unsupervised technique used to group similar data points based on shared characteristics, not to predict specific numeric outcomes.

Therefore, because predicting a sale price involves forecasting a continuous numerical value, the correct model type is Regression.

This aligns with Microsoft’s AI-900 teaching that regression is used for tasks such as:

Predicting house prices

Forecasting sales revenue

Estimating car values or auction prices

According to the Microsoft Azure AI Fundamentals (AI-900) official study guide and the Microsoft Learn module “Identify features of common machine learning types”, there are three main types of machine learning: supervised learning, unsupervised learning, and reinforcement learning. Within supervised learning, two common approaches are regression and classification, while clustering is a primary example of unsupervised learning.

“You train a regression model by using unlabeled data.” – No.Regression models are trained with labeled data, meaning the input data includes both features (independent variables) and target labels (dependent variables) representing continuous numerical values. Examples include predicting house prices or sales forecasts. Unlabeled data (data without target output values) cannot be used to train regression models; such data is used in unsupervised learning tasks like clustering.

“The classification technique is used to predict sequential numerical data over time.” – No.Classification is used for categorical predictions, where outputs belong to discrete classes, such as spam/not spam or disease present/absent. Predicting sequential numerical data over time refers to time series forecasting, which is typically a regression or forecasting problem, not classification. The AI-900 syllabus clearly separates classification (categorical prediction) from regression (continuous value prediction) and time series (temporal pattern analysis).

“Grouping items by their common characteristics is an example of clustering.” – Yes.This statement is correct. Clustering is an unsupervised learning technique used to group similar data points based on their features. The AI-900 study materials describe clustering as the process of “discovering natural groupings in data without predefined labels.” Common examples include customer segmentation or document grouping.

Therefore, based on Microsoft’s AI-900 training objectives and definitions:

Regression → supervised learning using labeled continuous data (No)

Classification → categorical prediction, not sequential numeric forecasting (No)

Clustering → grouping by similarity (Yes)