Principal Component Analysis (PCA) is the gold standard in dimensionality reduction.
But PCA is hard to understand for beginners.
Let me destroy your confusion:
1. What is PCA?
PCA is a statistical technique used in data analysis, mainly for dimensionality reduction. It's beneficial when dealing with large datasets with many variables, and it helps simplify the data's complexity while retaining as much variability as possible.
2. PCA has 5 steps:
1. Standardization 2. Covariance Matrix Computation 3. Eigen Vector Calculation 4. Choosing Principal Components 5. Transforming the data
K-means is an essential algorithm for Data Science.
But it's confusing for beginners.
Let me demolish your confusion:
1. K-Means
K-means is a popular unsupervised machine learning algorithm used for clustering. It's a core algorithm used for customer segmentation, inventory categorization, market segmentation, and even anomaly detection.
2. Unsupervised:
K-means is an unsupervised algorithm used on data with no labels or predefined outcomes. The goal is not to predict a target output, but to explore the structure of the data by identifying patterns, clusters, or relationships within the dataset.
R-squared is one of the most commonly used metrics to measure performance.
But it took me 2 years to figure out mistakes that were killing my regression models.
In 2 minutes, I'll share how I fixed 2 years of mistakes (and made 50% more accurate models than my peers). Let's go:
1. R-squared (R2):
R2 is a statistical measure used in regression models that provides a measure of how well the observed outcomes are replicated by the model, based on the proportion of total variation of outcomes explained by the model.
2. Range (0 to 1):
R2 ranges from 0 to 1. A higher R2 value indicates a better fit between the prediction and the actual data. For example, an R2 value of 0.70 suggests that 70% of the variance in the dependent variable is predictable from the independent variable(s).
Correlation is the skill that has singlehandedly benefitted me the most in my career.
In 3 minutes I'll demolish your confusion (and share strengths and weaknesses you might be missing).
Let's go:
1. Correlation:
Correlation is a statistical measure that describes the extent to which two variables change together. It can indicate whether and how strongly pairs of variables are related.
2. Types of correlation:
There are several types of correlation used in statistics to measure the strength and direction of the relationship between variables. The three most common types are: Pearson, Spearman Rank, and Kendall's Tau. We'll focus on Pearson since that is 95% of the time what I use.