R Language Basics

The post is about some R Language Basic Questions. The questions are related to the use of R Language, some preliminaries in R, the Use of Rstudio, R Commander, some functions in R, etc.

R Language Basic Questions

What is Rstudio and how to use it?

The Rstudio is software used as an editor for writing R and other Language-related programming codes. To use Rstudio, follow the steps:

Step 1: Download and Install Rstudio
Step 2: Open Rstudio
Sep 3: Click on the menu: File -> New -> R Script
Step 4: Paste the R code (write it) in the new source code area. Running the R program on the command line or elsewhere will start the console. One can paste the R code in the R Console or editor area.
Step 5: Click the “Source” button above the code area.

One can also use the console in Rstudio. If a user clicks “Run” instead of “Source” user input might not work properly. One can use the R documentation.

What are Preliminaries in R?

The following are some preliminaries in R Language:

• R is a case-sensitive language
• # is the comment tag
• R is installed with the default library (also called packages). One can add/import extra packages to the library using the command library().
• To use a library function one must load it first into the memory using the command load().
• Variable names in R language cannot start with “.” (dot), “+” (plus sign), or “=” (minus sign).

Explain What is R

R is a data analysis software that is used by analysts, quants, statisticians, data scientists, and others. R Language is a leading tool for statistics, machine learning, and data analysis. It allows for the easy creation of objects, functions, and packages.

List out some of the functions that the R Language Provides

The following is a short list of functions that R provides:

• mean()
• median()
• var()
• lm()
• summary()
• print()
• glm()
• plot()

Explain How One Can Start the R Commander GUI

To start the R Commander, type the command, library(Rcmdr) into the R console. Note that one must first install the Rcmdr package.

install.packages("Rcmdr")
# Start the R Commander GUI
library(Rcmdr)

What is R Software for Statistics and Data Analysis

R is an open-source programming language. It is a software environment for statistical computing and graphics techniques. The R language is widely used by statisticians and data miners for developing statistical software/packages and performing data analysis.

What is Mean in R?

The mean is the average of the numbers: a calculated “central” value of a set of numbers. To calculate the mean of a data set, add up all the numbers, then divide by how many numbers there are. In R, one can do this by using the command:

x = c(1, 2, 4, 7, 8, 9, 4, 8)
mean(x)

What is the Median in R?

The Median is the “middle” of a sorted list of numbers. For an even amount of numbers, things are slightly different. In the case of an even number of observations, one can find the middle pair of numbers, and then find the average of these two middlemost numbers. The median can be computed in R by using the command:

x = c(1, 2, 4, 7, 8, 9, 4, 8)
median(x)

Note that R itself decides about a number of observations either there are even or odd number of observations.

Statistics for Data Analysts

The post is about R Language Interview Questions. It contains some basic questions that are usually asked in job interviews and examinations vivas.

R Language Interview Questions

What is R Programming?

R is a statistical and mathematical programming language and environment for statistical computing and plotting of graphics. It is similar to the S programming language which was developed by Bell Laboratories.

R Can be considered as a different implementation of S language, however, there are some important differences but much of the code can be written for S runs unaltered under R Language.

R is a powerful and versatile programming language that has gained immense popularity in the field of data science.

What Operating Systems Can R Support?

R Language is available as Free Software under the terms of the Free Software Foundation’s GNU General Public License in source code form. It compiles and runs on a wide variety of UNIX platforms and similar systems (including Linux and FreeBSD), and MacOS, Windows.

What are the Advantages of the R Language?

• R is open-source Free software. Hence anyone can use and change it.
• R is cross-platform which runs on many operating systems and different hardware. It can also run on 32-bit & 64-bit processors.
• R is good for GNU/Linux and Microsoft Windows.
• In R, anyone is welcome to provide bug fixes, code enhancements, and new packages.
• It is used for managing and manipulating data.
• The R Language is the most comprehensive statistical analysis package as new technology and ideas often appear first in R.
• R Language provides a wide variety of statistical tools (summary statistics, classical statistical tests, linear and nonlinear modeling, time-series analysis, classification, clustering, etc.), enhanced graphical techniques, and is highly extensible.
• The graphical capabilities of the R Language are good.
• One of R’s strengths is the ease with which enhanced publication-quality plots/graphs can be produced that may include mathematical symbols and formulae where needed.

What are the Disadvantages of R?

• In R language, the quality of some packages is less than perfect.
• In R, no one to complain, if something does not work.
• R is an application software that many people devote their own time to developing.
• R commands give little thought to memory management, and so R can consume all available memory.

Why R Language?

• It is free and open source.
• Provides a variety of statistical tools for data analysis.
• Have strong and well-defined graphical capabilities.
• Runs on different operating systems and hardware.
• Powerful capabilities related to data, Data management, and manipulation.
• Thousands of free R packages developed by experts.
• Free updates of R software and packages.

What does not R Language do?

• Though R is a programming language and it can easily connect to DBMS it is not database software.
• R does not consist of a user-friendly graphical user interface (GUI).
• Though it connects to Excel/Microsoft Office easily, R language does not provide a simple to advanced spreadsheet view of data.

Explain the R Environment

R is an integrated suite of software facilities for data manipulation, calculation, and graphical display. It includes:

• An effective data manipulation/handling and storage facility,
• A suite of operators for calculations on arrays, in particular vectors and matrices,
• A large, coherent, integrated collection of intermediate tools for data analysis,
• Graphical facilities for data analysis and display either on-screen or on hardcopy.
• A well-developed, simple, and effective programming language that includes conditionals, loops, user-defined recursive functions, input and output facilities, and file handling.

What are the uses of R Language?

Uses of R Language are

• Data Science: R is widely used in data science for tasks such as data cleaning, exploratory data analysis, statistical modeling, and machine learning.
• Academic Research: R language is a popular choice for researchers in various fields, such as statistics, economics, biology, and social sciences.
• Business Analytics: R language can be used to analyze business data, identify trends, and make informed decisions.
• Finance: R is used in finance for risk management, portfolio analysis, and quantitative trading.

statistics for data science and business analysis

The post is about R Language Job Interview Questions. It contains some basic questions that are usually asked in job interviews and examinations vivas.

R Language Job Interview Questions

The following are R FAQs Interview Questions with their detailed answers:

What are the Capabilities of the R Language?

The following are the capabilities of the R Language:

• Data Handling Capabilities: Good data handling capabilities and options for parallel computation.
• Availability/Cost: R languages is an open source, one can use it anywhere and free of cost.
• Advancement in Tool: R gets the latest features and updates frequently.
• Ease of Learning: R language has a steep learning curve. On the other hand, R is a low-level programming language, as a result, simple procedures can take long codes.
• Graphical capabilities: R has the most advanced graphical capabilities.
• Job Scenario: It is a better option for start-ups and companies looking for cost efficiency.
• Customer Service support and community: R is the biggest online growing community.

Explain a Few Features to Write R Code that Runs Faster.

R Language is a popular and famous statistical software for its enormous amount of packages. The syntax of R language is very flexible making it convenient at the cost of performance. R is indeed slow compared to many other scripting languages, but there are a few tricks that can make our R code run faster.

• Use a matrix instead of a data frame whenever possible. Data frames cause problems in many cases. Only use data frame when necessary.
• Use double(n) to create a vector of length n instead of using code rep(0,n), and similar to others.
• Split big data objects (e.g., big data frame or matrix) into smaller ones, and operate on these smaller objects.
• Use vector and matrix operations if possible. These *apply functions are very helpful for this purpose.
• Use for each(i=1:n) %dopar% {} to do parallel computing if applicable. Even if a for loop is not parallelizable, for each(i=1:n) %do% {} is a better alternative.
• Avoid changing the type and size of an object in R language. Though one can use R objects as if they are typeless, they have type actually. In R, changing the type and size of an R object forces it to reallocate a memory space which is of course insufficient.
• Avoid creating too many objects in each working environment. Not having enough memory can not only make the code run slower but also make it fail to run if have to allocate big vectors. One way to do this is to write small functions and run the functions instead of running everything directly in a working environment.

What is Visualization in R?

Visualization is a technique for creating images, diagrams, or animations to communicate a message. Visualization through visual imagery has been an effective way to communicate both abstract and concrete ideas since the dawn of humanity. By using visual elements like charts, graphs, and maps, data visualization tools provide an accessible way to see and understand trends, outliers, and patterns in data.

Why R Language?

R is popular among researchers, data scientists, and statisticians. It is also used in finance, which relies heavily on statistical data. The R programming language is used for many reasons, including:

• Data analysis: R is a statistical programming tool well-suited for data analysis, mining, and modeling. It is also used for data cleaning and importing.
• Open-source and free: R is free and open-source and works on different platforms, including Windows, Mac, and Linux.
• Data visualization: R is a powerful tool for creating publication-ready graphics and visualizations, such as cluster bar charts, pie charts, histograms, box plots, and scatter plots.
• Machine learning: R is an effective tool for machine learning algorithms.
• Specialized focus on analysis: R handles specialized data science projects better than general-purpose software development languages like Python.
• Many packages: R has many packages (libraries of functions) that can be used to solve different problems.
• Large community support: R has a large community support.

What is SAS and SPSS in R?

SAS: SAS stands for Statistical Analysis System. It was primarily developed to be able to analyze large quantities of agriculture data.
SPSS: SPSS stands for Statistical Package for the Social Sciences and was developed for the social sciences.
R Language: R language was the first statistical programming language for the PC.

Computer MCQs Online Test, Chi-Square Distribution $\chi^2$