Interview question based on skill :
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Total Questions: 20
1. A _______________ is a variable that holds one value at a time.
Correct Answer is : Scalar variable
2. Which of the following return a subset of the columns of a data frame?
Correct Answer is : select
3. Point out the correct statement :
Correct Answer is : All of the mentioned
4. _________ extract a subset of rows from a dataframe based on logical conditions.
Correct Answer is : rename
5. _________ generate summary statistics of different variables in the data frame, possibly within strata
Correct Answer is : summarize
6. Point out the wrong statement :
Correct Answer is : The dplyr package provides any “new” functionality to R
7. ________ add new variables/columns or transform existing variables
Correct Answer is : mutate
8. The _______ operator is used to connect multiple verb actions together into a pipeline
Correct Answer is : pipe
9. The dplyr package can be installed from GitHub using the _______ package
Correct Answer is : devtools
10. The dplyr package can be installed from CRAN using :
Correct Answer is : install.packages(“dplyr”)
11. Which of the following object is masked from ‘package: stats’?
Correct Answer is : filter
12. Which of the following object is masked from ‘package: stats’?
Correct Answer is : filter
13. The _________ function can be used to select columns of a data frame that you want to focus on.
Correct Answer is : select
14. Point out the correct statement :
Correct Answer is : You can also omit variables using the select() function by using the negative sign
15. ________ function is similar to the existing subset() function in R but is quite a bit faster.
Correct Answer is : filter
16. Columns can be arranged in descending order too by using the special ____ operator.
Correct Answer is : desc()
17. Point out the wrong statement :
Correct Answer is : mute() function, which does the same thing as mutate() but then drops all non-transformed variables
18. The _________ function is used to generate summary statistics from the data frame within strata defined by a variable.
Correct Answer is : group_by()
19. The ______ operator allows you to string operations in a left-to-right fashion.
Correct Answer is : %>%
20. There is an SQL interface for relational databases via the _______ package.
Correct Answer is : DBI
