Understanding the Machine Learning Question Bank for a Tech Interview


Establishing a deep knowledge of machine learning is vital when applying for tech jobs. Beyond understanding its algorithms and implementation methods, understanding competitions like the Netflix Prize shows your dedication and knowledge of developments within this field.

1. What is Machine Learning?

Machine learning (ML) is an area of artificial intelligence (AI) that uses algorithms that develop themselves over time, becoming more accurate and effective as they process more data.

The technology used to search the web can also be applied in many other contexts: internet search engines use it to identify results; email filters use it to filter spam; banking software uses it to detect irregular transactions; and mobile apps use it to recognize voice commands. Self-driving cars rely on this technology, too – using it to interpret sensor data autonomously so they can navigate roads autonomously.

Machine learning’s primary purpose is to help humans perform tasks they are either incapable of or take too much time to do, like recognizing people or objects from images. Even when designed as objective programs, human biases may still leak into them and negatively influence outcomes.

2. What is Deep Learning?

Machine learning is a branch of artificial intelligence in which computers automatically learn and adapt to data without human programmers’ help. Machine learning models use data they analyze for new tasks like solving complicated math equations or forecasting weather events.

Machine learners are capable of processing information based on patterns but are limited in terms of how many variables they can extract and transform. To overcome this limitation, feature engineering involves selecting those most crucial to a model’s goal as the focal variables for extraction and transformation.

Deep learning is an advanced form of machine learning that allows computers to understand a wider variety of inputs more quickly. It consists of multiple layers of algorithms inspired by brain structures to form complex understandings – it powers everything from facial recognition and tagging photos online to self-driving cars and intelligent voice assistants.

3. What is One-Hot Encoding?

Most Machine Learning algorithms require input and output variables/features to be in numerical format, making categorical data difficult to convert easily; as such, one-hot Encoding may be used as a practical preprocessing step.

One-Hot Encoding converts categorical variables to binary vectors where each value is represented by one ‘1’ while all others remain at zero, helping machine learning models work with categorical data more efficiently.

Using this method can also help avoid ordinality problems that could misinterpret results if a model assumes natural order between categories while simultaneously leading to high-dimensional data and multicollinearity that reduce model accuracy. Therefore, it is crucial that before deciding to implement this technique, you carefully assess both its advantages and disadvantages.

4. What is Label Encoding?

Label encoding is a method of translating categorical features to numeric values for more accessible data analysis and machine learning, as well as improved model performance.

Machine learning algorithms tend to perform better with numerical data than with categorical. Furthermore, numerical data helps reduce memory usage, which is helpful when working with large datasets.

Label encoding may not always be suitable for every dataset or situation; for instance, its algorithms could misunderstand it when dealing with nominal categorical data that doesn’t have an obvious hierarchy (e.g., country names).

Before choosing this method of data preprocessing, it’s essential to carefully consider your dataset and machine learning model’s requirements when making this decision. One-hot encoding may be more suitable in these instances.

5. What is Neural Networks?

Neural networks are intelligent machine learning algorithms inspired by human neural structures. Composed of interconnected nodes (artificial neurons), neural networks are designed to process complex data sets, recognize patterns within them, and make predictions or decisions based on this knowledge.

Neural networks excel at handling unstructured data and have applications in numerous industries, including chatbots, autonomous vehicles, cybersecurity, agriculture, and product recommendations. Medical researchers also employ neural networks for diagnosing disease’s underlying causes. But neural networks do have some drawbacks that must be considered, including their complexity and lack of transparency – such as difficulty in understanding decision-making processes when fed biased training data sets – plus training costs and high-performance computing requirements are often significant, thus making neural networks not suitable for every problem solution.

6. What is Bayes’ Theorem?

Bayes’ Theorem is an elegant mathematical formula that can help us calculate the likelihood of events given new evidence. Although often applied in statistical analysis, Bayes’ Theorem can be used in any situation where we know both an event and its outcome.

Assuming we have evidence that 0.5% of those taking a particular drug are misusing it, Bayes’ Theorem can help us predict whether someone randomly selected will test positive.

Bayes’ Theorem is one of the cornerstones of machine learning, playing an essential role in how new data should be integrated into existing models and why our beliefs should adapt proportionately with each new piece of evidence we encounter. Furthermore, Bayes’ Theorem forms a vital part of subjectivist approaches to epistemology and statistics.

7. What is Boosting?

Boosting is an ensemble method used to combine weak learners to form more robust models, employing techniques like reweighting to increase prediction accuracy and manage class imbalance.

AdaBoost, Gradient Boosting, and XGboost are popular boosting algorithms. Each works similarly, differing only in how weights are adjusted and which algorithm is employed at every step in the process. Boosting algorithms often focus on errors made by previous weak models – for instance, if an algorithm missed a picture of a dog with its pug nose being missed by one soft model, it will place more importance on that instance in future models.

Boosting is less susceptible to overfitting than other ensemble methods like bagging. This makes it an attractive choice for applications requiring more interpretable rules; its only drawback is the computational cost when dealing with multiple weak learners.

8. What is Support Vector Machines?

Support vector machines (SVMs) are supervised learning models used for classification, regression, density estimation, and novelty detection tasks. Support vector machines excel over other linear algorithms in nonlinear problems while providing effective generalization onto unseen data sets.

Fast and versatile, neural nets offer immediate results with only a few thousand samples tagged. This makes them especially suitable for text classification tasks like sentiment analysis or spam detection.

SVMs work by identifying an optimal hyperplane (in two dimensions, this would be a straight line) to separate two classes of data points. They do this by transforming their input data into higher-dimensional feature spaces – known as kernelling – which helps lift decision surfaces and makes linear separation more likely for SVMs. Training an SVM involves solving a quadratic optimization problem to find an ideal hyperplane that minimizes the soft margin between classes.

9. What is Classification?

Classification is the process of grouping objects into classes according to similarities or affinities, making up an essential element in many sciences, including biology, knowledge organization, and statistics.

Classification algorithms use information in training datasets to predict class labels of new data sets, for instance, identifying emails as spam or not. Their performance can be assessed through confusion matrices that list how many correct and incorrect predictions they made during testing.

Some classification tasks only need two classes, like photos or text, which is known as binary classification. Other classification problems require more nuanced predictions, such as probabilistic analysis of whether an example belongs to one particular class – known as phenetics or numerical taxonomy.

10. What is Clustering?

Clustering is a machine learning technique used to organize data into groups with similar examples, often seen in fields such as biology, medical science, marketing research, and customer classification.

Cluster analysis is an excellent way to organize and visualize datasets, helping you gain clarity into them while uncovering insights that would otherwise remain hidden from view.

Clustering algorithms come in many varieties, from K-means, BIRCH, and DBSCAN to density-based clustering and more. Each has its approach and purpose; selecting one for your dataset requires careful mathematical consideration as well as consulting domain or business experts until you find an approach and settings combination that suits it perfectly.