## What is Bagging in Ensemble Learning In general, any of the machine learning problems we try to find the best possible optimal model for a given problem. That means finding the best possible model within the given model family, for example, finding the best possible decision tree or finding the best possible KNN model. And if we have more time then we can try all model families available, and come up with the best possible regression model, best possible KNN model, best possible SVM model etc. And among these again select the best possible model, which will be either KNN, SVM or any other.

## How to start career in Data Science and Machine Learning It does not matter how much experience you have, actually anybody can start or switch to data science and machine learning. The only important this is, how much eager you are for it. What it means to you. If you are very much keen to work in this field then nobody can stop you. There might be some short term hurdles however if you are focused enough and know your goals regarding where you want to see yourself after certain years, then you will definitely be successful in overcoming those hurdles.

## Bayes’ Theorem with Example for Data Science Professionals Bayes Theorem is the extension of Conditional probability. Conditional probability helps us to determine the probability of A given B, denoted by P(A|B). So Bayes’ theorem says if we know P(A|B) then we can determine P(B|A), given that P(A) and P(B) are known to us.

## Variance, Standard Deviation and Other Measures of Variability and Spread Variance and Standard Deviation are the most commonly used measures of variability and spread. Variability and spread are nothing but the process to know how much data is being varying from the mean point. And Variance tells us the average distance of all data points from the mean point. Standard deviation is just the square root of the variance. As variance is calculated in squared unit (explained below in the post) and hence to come up a value having unit equal to the data points, we take square root of the variance and it is called as Standard Deviation.

## Step by Step Approach to Principal Component Analysis using Python Principal Component Analysis or PCA is used for dimensionality reduction of the large data set. In my previous post A Complete Guide to Principal Component Analysis – PCA in Machine Learning , I have explained what is PCA and the complete concept behind the PCA technique. This post is in continuation of previous post, However if you have the basic understanding of how PCA works then you may continue else it is highly recommended to go through above mentioned post first.

## What is the Coefficient of Determination | R Square The coefficient of Determination is the direct indicator of how good our model is in terms of performance whether it is accuracy, Precision or Recall. In more technical terms we can define it as The Coefficient of Determination is the measure of the variance in response variable ‘y’ that can be predicted using predictor variable ‘x’. It is the most common way to measure the strength of the model.

## What is Linear Regression? Part:1 Linear Regression is a field of study which emphasizes on the statistical relationship between two continuous variables known as Predictor and Response variables. (Note: when there are more than one predictor variables then it becomes multiple linear regression.)

• Predictor variable is most often denoted as x and also known as Independent variable.
• Response variable is most often denoted as y and also known as Dependent variable. 