1. Which of the following variable names are INVALID in R?

• 1_variable
• variable_1
• _variable
• variable@

Answer :-a. 1_variable, c. _variable, d. variable@, 

2. The function ls() in R will

• set a new working directory path
• list all objects in our working environment
• display the path to our working directory
• None of the above

Answer :- b. list all objects in our working environment

3. Which of the following command is used to access the value “Shyam”?

• print(patient_list[3][2])
• print(patient_list[[3]][1])
• print(patient_list[[3]][2])
• print(patient_list[[2]][2])

Answer :- c. print(patient_list[[3]][2])

4. The output of the code given below is

• Code will throw an error

Answer :-  c. 

5. What is the output of following code?

• double
• integer
• list
• None of the above

Answer :-  a. double

6. State whether the given statement is True or False.
The library reshape2 is based around two key functions named melt and cast.

• True
• False

Answer :- True

7. What is the output of following code?

• 6
• 4
• 2
• 8

Answer :-  b. 4

8. Choose the correct command to add a column named student_dept to the dataframe student_data.

• student_datastudent_dept=c(“Commerce”, “Biology”, “English”, “Tamil”)
• student_data[“student_dept”]= c(“Commerce”,“Biology”, “English”,“Tamil”)
• student_dept= student_data[c(“Commerce”,“Biology”,“English”,“Tamil”)]
• None of the above

Answer :- a. student_data$student_dept = c("Commerce", "Biology", "English", "Tamil"), 
b. student data[“student dept”]= c(“Commerce”,“Biology”, “English”,“Tamil”)

9. Choose the correct command to access the element Tamil in the dataframe student_data.

• student_data[[4]]
• student_data[[4]][3]
• student_data[[3]][4]
• None of the above

Answer :- c. student_data[[3]][4]

10. The command to check if a value is of numeric data type is ____.

• typeof()
• is.numeric()
• as.numeric()
• None of the above

Answer :- b. is.numeric()