Muhammad Imdad Ullah

Student and Instructor of Statistics and business mathematics. Completed my Ph.D. in Statistics from the Department of Statistics, Bahauddin Zakariya University, Multan, Pakistan. l like Applied Statistics, Mathematics and Statistical Computing. Statistical and Mathematical software used is SAS, STATA, GRETL, EVIEWS, R, SPSS, VBA in MS-Excel. Like to use type-setting LaTeX for composing Articles, thesis, etc.

Important R Language Questions

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The post is about R Language Questions that are commonly asked in interviews or R Language-related examinations and tests.

R Language Questions

Question: What is a file in R?
Answer: A script file written in R has a file extension of R. Since, R is a programming language designed to perform statistical computing and graphics on given data, that is why, a file in R contains code that can be executed within the R software environment.

Question: What is the table in R?
Answer: A table in R language is an arbitrary R object, that is inherited from the class “table” for the as.data.frame method. A table in R language refers to a data structure that is used to represent categorical data and frequency counts. A table provides a convenient way to summarize and organize the data into a tabular format, making it easier to analyze and interpret.

Factor Variables in R

Questions: What is the factor variable in R language?
Answer: Factor variables are categorical variables that hold either string or numeric values. The factor variables are used in various types of graphics, particularly for statistical modeling where the correct number of degrees of freedom is assigned to them.

Data Structure in R

Questions: What is Data Structure in R?
Answer: A data structure is a specialized format for organizing and storing data. General data structure types include the array, the file, the record, the table, the tree, and so on. R offers several data structures, each with its characteristics and purposes. In R common data structures are: vector, factor, matrix, array, data frame, and lists.

scan() Function in R

Question: What is a scan() in R?
Answer: The scan() in R is used to Read Data Values: Read data into a vector or list from the console or file. For Example:

Z <- scan()
1: 12 5
3: 2
4:
Read 3 items

> z
[1] 12 5 2
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readline() Function in R

Questions: What is readline() in R?
Answer: The deadline() function in R, read text lines from a Connection: Read some or all text lines from a connection. One can use readline() for inputting a line from the keyboard in the form of a string. For Example:

w <- readline()
xyz vw u
> w

[1] "xyz vw u"

R and Data Analysis

MCQs in Statistics

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Important MCQs R Markdown Quiz 12

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Online MCQs R Markdown Quiz with Answers. R Markdown is a way of generating fully reproducible documents, in which both text and code can be combined. Let us start with the MCQs R Markdown Quiz.

Online MCQs about R Markdown with Answers

1. If an analyst creates the same kind of document over and over or customizes the appearance of a final report, they can use __________ to save them time.

 
 
 
 

2. A data analyst wants to create documentation for their cleaning process so other analysts on their team can recreate this process. What tool can help them create this shareable report?

 
 
 
 

3. A data analyst has finished editing their R Markdown file and wants to save it as an HTML report. What tool will they use?

 
 
 
 

4. What is the purpose of the Knit button in R Studio?

 
 
 
 

5. A data analyst wants to embed a link in their RMarkdown document. They write (click here!)(www.rstudio.com) but it doesn’t work. What should they write instead?

 
 
 
 

6. What information does a data analyst usually find in the header section of an RMarkdown document?

 
 
 
 

7. Fill in the blank: Markdown is a _________ for formatting plain text files.

 
 
 
 

8. A data analyst has code chunks in their R Markdown file. How do they appear in an HTML report?

 
 
 
 

9. To create bullet points in their output document, a data analyst adds __________ to their RMarkdown document.

 
 
 
 

10. A data analyst wants to find headers in their R Markdown document. What should they look for?

 
 
 
 

11. A data analyst notices that their header is much smaller than they wanted it to be. What happened?

 
 
 
 

12. A data analyst needs to create a shareable report in RStudio. They first want to change the default file format that gets exported by the Knit button to .pdf. What value should they use for the output field in the YAML header?

 
 
 
 

13. A data analyst creates an interactive version of their R Markdown document to share with other users allowing them to execute code the analyst wrote. What did they create?

 
 
 
 

14. R Markdown notebooks can be converted into HTML, PDF, and Word documents, slide presentations, and _________.

 
 
 
 

15. A delimiter is a character that indicates the beginning or end of __________.

 
 
 
 

16. A data analyst wants to convert their R Markdown file into another format. What are their options?

 
 
 
 

MCQs R Markdown Quiz

MCQs R Markdown Quiz

  • A data analyst wants to find headers in their R Markdown document. What should they look for?
  • A data analyst has code chunks in their R Markdown file. How do they appear in an HTML report?
  • Fill in the blank: Markdown is a ———- for formatting plain text files.
  • A data analyst creates an interactive version of their R Markdown document to share with other users allowing them to execute code the analyst wrote. What did they create?
  • A data analyst wants to convert their R Markdown file into another format. What are their options?
  • A data analyst has finished editing their R Markdown file and wants to save it as an HTML report. What tool will they use?
  • What information does a data analyst usually find in the header section of an RMarkdown document?
  • To create bullet points in their output document, a data analyst adds ———- to their RMarkdown document.
  • A data analyst wants to embed a link in their RMarkdown document. They write (click here!)(www.rstudio.com) but it doesn’t work. What should they write instead?
  • A data analyst needs to create a shareable report in RStudio. They first want to change the default file format that gets exported by the Knit button to .pdf. What value should they use for the output field in the YAML header?
  • What is the purpose of the Knit button in R Studio?
  • A delimiter is a character that indicates the beginning or end of ———-.
  • R Markdown notebooks can be converted into HTML, PDF, and Word documents, slide presentations, and ———-.
  • A data analyst notices that their header is much smaller than they wanted it to be. What happened?
  • A data analyst wants to create documentation for their cleaning process so other analysts on their team can recreate this process. What tool can help them create this shareable report?
  • If an analyst creates the same kind of document over and over or customizes the appearance of a final report, they can use ———- to save them time.

MCQs in Statistics, R Data Analysis

R Language Basics and R FAQs: Learning Made Easy

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The post is about R Language Basics and R Language Frequently Asked Questions. The contents are in the form of questions and answers. Let us start with R Language Basics Questions and Answers.

R Basics

Question: How to start (Run) R Language in the Windows Operating System?
Answer: In Microsoft Windows, during installation, the R installer will have created a Start menu item and an icon for R on your system’s desktop. Double-click the R icon from the desktop or the start menu list to Run the R program.

For Windows 7, 8, or 10, you can use a search term like “R x64 3.2.1” (64-bit version) or “R i386 3.2.1” (32-bit version). R GUI will launch.

Using R as a Calculator

Question: How R can be used as a calculator?
Answer: One can easily use R as a calculator. Starting R will open the console where the user can type commands. To use R as a calculator one has to enter the arithmetical expression after > prompt. For example

5 + 4
sqrt(37)
2*4^2+17*4-3
R language Basics and R as Calculator

R Workspace

Question: What is a workspace in R?
Answer: The workspace in R is an image that contains a record of the computations one has done and it may contain some saved results.

Question: How to record works[ace in R?
Answer: Rather than saving the workspace, one can record all the commands that one has entered in the R console. Recording work in R, the R workspace can be reproduced. The easiest way is to enter the commands in R’s script editor available in the File menu of R GUI.

R Script Editor

Question: What is R Script Editor?
Answer: The r script editor is a place where one can enter commands. Commands can be executed by highlighting them and hitting CTRL+R (mean RUN). At the end of an R session, one can save the final script for a permanent record of one’s work.

A text editor such as Notepad can also be used for this purpose.
Note that in the R console, only one command can be entered at a time because after pressing the Enter key the R command executed immediately.

Quitting R Session

Question: How to quit the R session?
Answer: In the R console on the R command prompt just type

q( )

Question: What is q()?
Answer: The q() is a function that is used to tell R to quit. When q() is entered in the R console and press the Enter key, you will be asked whether to save an image of the current workspace or not or to cancel. Note that only typing q tells R to show the content of this function. The action of this function is to quit R.

Frequently Asked Questions About R

MCQs Statistics with Answers

Computer MCQs Online Test