Machine learning algorithms for beginners | Data Science

Machine learning algorithms for beginners | Data Science

You know how every time you enter your Netflix account, you get tons of new recommendations for movies/TV shows that you might like?

Well, let’s be honest. We like most of those recommendations. And, most people do, actually. In fact, 75% of Netflix subscribers choose the films suggested to them by the company’s machine learning algorithms. These algorithms learn from your behaviour in the app to show you the content you’re most likely to play. 

Machine learning is a form of data processing that automates the development of analytical models. It’s a subset of artificial intelligence focused on the premise that computers can learn from data, recognize patterns, and decide things with little to no human input. As machine learning enables machines to learn from data, it has become one of the most buzzed words in computer science during the past few years. 

Machine learning is changing the world: from filtering ads in social media to computer vision for self-driving vehicles, machine learning has a wide range of uses. According to Markets and Markets, the machine learning market is projected to rise at a CAGR of 44.1%, from $1.03 billion in 2016 to $8.81 billion in 2022. 

AI and machine learning are transforming consumer experience, according to 83% of IT executives, and 69% state that these technologies are transforming their businesses. According to 79% of respondents in the survey by Salesforce, AI would assist their company in identifying external and internal security risks.

The rise of the machine learning market and the increasing adoption of this technology in many companies will also increase the demand for professionals proficient with ML algorithms. So, if you’ve been thinking about a career in this field, you’re moving in the right direction. 

With this post, we want to give you a quick introduction to the ML world. After reading this article, you will be able to comprehend the simple reasoning behind some of the most common and highly resourceful machine learning algorithms that are most commonly used in data science today. 

How does Machine Learning work? 

Machine learning is a form of artificial intelligence (AI) that teaches machines to act as humans do: by learning from and developing on previous experiences. It operates by analyzing data and finding trends with no human involvement.

Machine learning can simplify almost every task that can be performed using a data-defined formula or series of rules. This enables businesses to automate tasks that historically required humans to complete, such as answering customer service requests, recordkeeping, and checking resumes.

Machine learning algorithms for beginners | Data Science

To put it simply, here’s how a machine learning model works: 

  • Making a forecast
  • Validation of the forecast
  • Error measurement
  • Changing the model’s proportions in an attempt to reduce the error 
  • Making a new forecast

This is an iterative process that keeps repeatedly happening, representing the resource-rich part of machine learning. The system keeps learning as the process repeats.


Types of ML algorithms

There are three types of machine learning: supervised learning, unsupervised learning, and reinforcement learning. In the next part, we’ll explain these three types of ML and introduce you to the most important algorithms of each type. 

Supervised learning

To map an input to output, supervised learning uses example input-output pairs. It infers a feature from labelled training data that consists of a set of training examples. Each example in supervised learning is a pair containing an input object and a target output value.

A supervised learning algorithm evaluates the training data and generates an assumed function that can be used to produce various instances. An ideal situation will allow the algorithm to determine the class labels in unseen cases correctly. This enables the learning algorithm to produce previously unknown scenarios by rationally generalizing from the training results.

Supervised learning is about predicting what you’ve seen before. You want to determine if the operation’s outcome was in the past to create a system that tries to extract the critical data about the next time it happens to make forecasts.

When forecasting who will win a sporting game, for example, supervised learning may be helpful. In this scenario, the machine may depend on previous related events’ outcomes. Social networks can also use this approach to determine which ad or content category you can select next.

Predicting real estate values is another example of supervised learning. You’ll need information about the estates, such as features, square feet, and the number of rooms, among other things. The stickers will be the estates’ current values. A supervised machine learning algorithm can estimate the price of a new real estate by analyzing this form of data with many estates.

Predicting real estate values is another example of supervised learning. You’ll need information about the estates, such as features, square feet, and the number of rooms, among other things. The labels will be the estates’ current values. A supervised machine learning algorithm can estimate the price of a new real estate by analyzing this form of data with many estates.

Supervised learning is divided into regression and classification.

After learning from labelled datasets, regression will predict the continuous-valued performance of new data introduced to the algorithm. If the data is numerical, scientists can use it. These are the most common regression algorithms:

  • Linear regression assumes that the relationship between the input and output, as well as the data from which they are derived, is linear. The input is treated as an independent variable, while the output is treated as a dependent variable. To learn more about linear regression, check this article
  • By mapping unseen data to the logic function built into it, logistic regression predicts discrete values for the independent variables. The algorithm calculates the likelihood of new data with an output between 0 and 1.

Classification is a method of learning in which the algorithm attempts to map new data acquired from the dataset to one of the two groups. In contrast to regression, where the outcome was a number between 0 and 1, here, the outcome is either 1 or 0. In real life, this type of learning predicts whether or not anything will occur, so the performance is yes or no. The following are a few of the most widely used classification algorithms:

  • The dataset is the root of the Decision Tree, which analyzes the data collection properties to determine which one has the most essential knowledge.
  • In the case of large datasets, Naive Bayes classifies the dataset properties independently.
  • Support Vector Machines are based on the Vap Nik mathematical principle and define the two groups using the Kernel method.


 Unsupervised learning 

Unsupervised learning is a form of machine learning that leverages data sets without previously established tags to search for undetected patterns with minimal human supervision. Unsupervised learning facilitates the simulation of probability densities over inputs, unlike supervised learning that typically uses human-labelled data.

Unsupervised learning leaves the target outcome behind and uses only the existing data to make predictions. This method of machine learning is less concerned with making predictions than with recognizing and defining connections or correlations within the data that might occur. Unsupervised learning determines relationships within the data that’s already available. 

For example, with unsupervised learning, you can separate your target customers into segments. You can perform this by using clustering algorithms, an unsupervised learning technique we’ll explain further. You basically segment the data points in such a way that every data point fits into a group based on a particular feature identical to other data points in the same group.

There are two types of unsupervised learning: clustering and association. 

Clustering and association are the two types of unsupervised learning. 

Clustering defines trends in datasets and divides them into groups dependent on different characteristics. Clustering can be: 

  • Hierarchical, in which datasets are grouped based on how close the data points are.
  • K-Means, in which the algorithm measures the cluster’s centroid to construct clusters of as many homogeneous data points as possible. The variation between the centroid and the data points can be as slight as possible, resulting in clusters that can be named since they have data points that are very close.
  • K-NN, in which the algorithm is only active when a new data point is received, and it uses the datasets it has stored to identify it. This algorithm isn’t suitable for massive datasets with a high number of new data points.

Association is an unsupervised learning form that locates and connects the relationships between one data item and another data item. The two most widely used association algorithms are:

  • Apriori determines a data point’s dependence on another, intending to determine what will happen if the data point from which it is based changes. Changes in the price of one commodity, for example, will affect the price of its complementary product.
  • The Frequency Pattern algorithm calculates the number of repeating patterns, adds it to a table, and then finds the most possible object to use as the tree’s root. Then, depending on the determined support, other elements are included. The object that decides the relationship should be indicated at the tree’s base.


Reinforcement learning

Reinforcement learning is a subset of machine learning that aids algorithms in learning from the outcomes of their own decisions. This is for a certain kind of problem where the decision-making process is linear, and the goal is long-term.

The agent learns to achieve a goal in an uncertain, potentially complicated environment. This seems to be a game in which the computer solves the problem by trial and error. To get the algorithm to do what the data scientist or developer wishes, artificial intelligence receives either rewards or penalties for its actions. It aims to maximize the total payoff. The target is to obtain the highest possible overall payout.

While supervised and unsupervised learning often uses static data and produce static outcomes, reinforcement learning uses a dynamic dataset that interacts with the real world. There are many examples, but the most well-known is when IBM’s Deep Blue AI defeated Gary Kasparov in a chess match in 1996. The machine used reinforcement learning to figure out which movements are good and which are bad by playing games and improving with each one.

In this article, we made a quick overview of the most common machine learning algorithms of each type: supervised, unsupervised, and reinforcement learning. Now you have a starting point to get deeper into machine learning and pursue a career in data science, which will be the job of the future.

Happy learning!

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