What is stepAIC in R?

In R, stepAIC is one of the most commonly used search method for feature selection. We try to keep on minimizing the stepAIC value to come up with the final set of features. “stepAIC” does not necessarily means to improve the model performance, however it is used to simplify the model without impacting much on the performance. So AIC quantifies the amount of information loss due to this simplification. AIC stands for Akaike Information Criteria.

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Feature Selection Techniques in Regression Model

Feature selection is a way to reduce the number of features and hence reduce the computational complexity of the model. Many times feature selection becomes very useful to overcome with overfitting problem. It helps us in determining the smallest set of features that are needed to predict the response variable with high accuracy. if we ask the model, does adding new features, necessarily increase the model performance significantly? if not then why to add those new features which are only going to increase model complexity.

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Important Use Cases of NLP

In today’s world we are generating large amount of data every second. while tweeting, chating, writing or even speaking, we are fabricating corpse of data. Most of the data is in textual and unstructured form. Hence to make this data understandable by computer, we need to process it. NLP technique helps us in processing the data and helps us to get useful insights from it.

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Basic Statistics for Data Science – Part 1

The Science of collecting, organizing, presenting, analyzing and interpreting the data is statistics. It is one of the most important disciplines or methods to get a deeper insight into data. Statistical analysis is implemented to manipulate, summarize and investigate data so that useful information can be obtained.populationvssample

Take away from this post:

  • Types of Statistics: Descriptive vs Inferential
  • Basic terminology like Population vs Sample
  • Types of Variables: Numerical vs Categorical
  • Measures of central tendencies: Mean, Median and Mode and their specific use cases
  • Measures of dispersion/spread: Variance, standard deviation etc.

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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.

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Employee Attrition Rate Analysis – Insights from IBM HR Data

Storytelling or presenting insights is the most important part of data analytics. This is the selling point of all your hard work. Doesn’t matter how much hard work you have put in developing analytic model until you are able to get the attention of the target audience. Here in this particular article, my focus is on how we can use beautiful graphs to show the insights regarding employee attrition rate from IBM HR Attrition data. After all, a picture is worth to thousands of words.

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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.
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Covariance and Correlation

Covariance and Correlation are very helpful in understanding the relationship between two continuous variables. Covariance tells whether both variables vary in same direction (positive covariance) or in opposite direction (negative covariance). There is no significance of covariance numerical value only sign is useful. Whereas Correlation explains about the change in one variable leads how much proportion change in second variable. Correlation varies between -1 to +1. If correlation value is 0 then it means there is no Linear Relationship between variables however other functional relationship may exist.

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What is Linear Regression? Part:2

In any business there are some easy to measure variables like : Age, Gender, Income, Education Level etc. and there are some difficult to measure variables like amount of loan to give, no of days a patient will stay in the hospital, price of the house after 10 years etc. So Regression is the technique which enables you to determine difficult to measure variables with the help of easy to measure variables.

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Necessary Privileges for Creating Database Links

A database link is a pointer in the local database that lets you access objects on a remote database. To create a private database link, you must have been granted the proper privileges. The following table illustrates which privileges are required on which database for which type of link:

Privilege Database Required For
CREATE DATABASE LINK Local Creation of a private database link.
CREATE PUBLIC DATABASE LINK Local Creation of a public database link.
CREATE SESSION Remote Creation of any type of database link.

To see which privileges you currently have available, query ROLE_SYS_PRIVS. For example, you could create and execute the following privs.sql script (sample output included):

SELECT DISTINCT PRIVILEGE AS "Database Link Privileges"
FROM ROLE_SYS_PRIVS
WHERE PRIVILEGE IN ( 'CREATE SESSION','CREATE DATABASE LINK',
                     'CREATE PUBLIC DATABASE LINK')

or just execute following query to see all the permissions for current user:
SELECT DISTINCT PRIVILEGE AS "Database Link Privileges" FROM ROLE_SYS_PRIVS

Source: Oracle Docs