Data Science Questions and Answers – Summarizing and Merging Data

This set of Data Science Multiple Choice Questions & Answers (MCQs) focuses on “Summarizing and Merging Data”.

1. Which of the following function gives information about top level data?
a) head
b) tail
c) summary
d) none of the mentioned
View Answer

Answer: a
Explanation: The function head is very useful for working with lists, tables, data frames and even functions.

2. Point out the correct statement.
a) head function work on string
b) tail function work on string
c) head function work on string but tail function do not
d) none of the mentioned
View Answer

Answer: d
Explanation: Both head and tail function do not work on strings.

3. Which of the following function is used for quantiles of quantitative values?
a) quantile
b) quantity
c) quantiles
d) all of the mentioned
View Answer

Answer: a
Explanation: In probability and statistics, the quantile function specifies, for a given probability in the probability distribution of a random variable, the value at which the probability of the random variable will be less than or equal to that probability.

4. Which of the following function is used for determining missing values?
a) any
b) all
c) is
d) all of the mentioned
View Answer

Answer: d
Explanation: In R, missing values are represented by the symbol NA.

advertisement
advertisement

5. Point out the wrong statement.
a) Common variables are used to create missingness vector
b) Common variables are used to cutting up quantitative variables
c) Common variables are not used to apply transforms
d) All of the mentioned
View Answer

Answer: c
Explanation: Common variables are not used to apply transforms.

6. Which of the following transforms can be performed with data value?
a) log2
b) cos
c) log10
d) all of the mentioned
View Answer

Answer: d
Explanation: Many common transforms can be applied to the data with R.

Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

7. Each observation forms a column in tidy data.
a) True
b) False
View Answer

Answer: b
Explanation: Each variable forms a column in tidy data.

8. Which of the following function is used for casting data frames?
a) dcast
b) ucast
c) rcast
d) all of the mentioned
View Answer

Answer: a
Explanation: Use acast or dcast depending on whether you want vector/matrix/array output or data frame output.

advertisement

9. Which of the following join is by default used in plyr package?
a) left
b) right
c) full
d) all of the mentioned
View Answer

Answer: a
Explanation: Join is faster in plyr package.

10. mutate function is used for casting as multi dimensional arrays.
a) True
b) False
View Answer

Answer: b
Explanation: mutate is used for adding new variables.

advertisement

Sanfoundry Global Education & Learning Series – Data Science.

Here’s the list of Best Books in Data Science.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & discussions at Telegram SanfoundryClasses.