**Here are some essential machine learning algorithms that every data scientist should know:**

Linear Regression: This is a supervised learning algorithm that is used for continuous target variables. It finds a linear relationship between a dependent variable (y) and one or more independent variables (X). It’s widely used for tasks like predicting house prices or stock prices.

Logistic Regression: This is another supervised learning algorithm that is used for binary classification problems. It predicts the probability of an event happening based on independent variables. It’s commonly used for tasks like spam email detection or credit card fraud detection.

Decision Tree: This is a supervised learning algorithm that uses a tree-like model to classify data. It breaks down a decision into a series of smaller and simpler decisions. Decision trees are easily interpretable, making them a good choice for understanding how a model makes predictions.

Support Vector Machine (SVM): This is a supervised learning algorithm that can be used for both classification and regression tasks. It finds a hyperplane that best separates the data points into different categories. SVMs are known for their good performance on high-dimensional data.

K-Nearest Neighbors (KNN): This is a supervised learning algorithm that classifies data points based on the labels of their nearest neighbours. The number of neighbours (k) is a parameter that can be tuned to improve the performance of the algorithm. KNN is a simple and easy-to-understand algorithm, but it can be computationally expensive for large datasets.

Random Forest: This is a supervised learning algorithm that is an ensemble of decision trees. Random forests are often more accurate and robust than single-decision trees. They are also less prone to overfitting.

Naive Bayes: This is a supervised learning algorithm that is based on Bayes’ theorem. It assumes that the features are independent of each other, which is often not the case in real-world data. However, Naive Bayes can be a good choice for tasks where the features are indeed independent or when the computational cost is a major concern.

K-Means Clustering: This is an unsupervised learning algorithm that is used to group data points into k clusters. The k clusters are chosen to minimize the within-cluster sum of squares (WCSS). K-means clustering is a simple and efficient algorithm, but it is sensitive to the initialization of the cluster centres.