A data file `data.txt` uses tabs as separators and has a header row. An analyst wants to load it into R and then check the structure of the resulting data frame. Which sequence of commands is correct?

data <- read.csv('data.txt', sep = '\t', header = TRUE); str(data)

data <- read.table('data.txt', sep = '\t', header = TRUE); str(data)

data <- read.csv2('data.txt', sep = '\t', header = TRUE); str(data)

data <- read.delim('data.txt', header = TRUE); str(data)

A data frame `patients` has a column `blood_pressure` with some missing values. An analyst wants to count how many missing values are in that column. Which R expression gives the count?

count(is.na(patients$blood_pressure))

table(is.na(patients$blood_pressure))

length(is.na(patients$blood_pressure))

sum(is.na(patients$blood_pressure))

Dell Data Science Foundations

Domain 3Objective 1

Explain How Basic R Commands Are Used to Initially Explore and Analyze the Data DATA-SCIENCE-FOUNDATIONS Practice Questions (Page 4)

Part of the Initial Analysis of the Data domain, which accounts for 15% of the DATA-SCIENCE-FOUNDATIONS exam.

24questions here

5free pages

7concepts

15%of the exam

Questions 16–20

16application · medium
A data file `data.txt` uses tabs as separators and has a header row. An analyst wants to load it into R and then check the structure of the resulting data frame. Which sequence of commands is correct?
Select an answer first
17application · easy
A data frame `students` has a column `grade` that contains values like 'A', 'B', 'C', and 'D'. An analyst wants to treat this column as a categorical variable with a fixed set of levels. Which R function is most appropriate to convert this column?
Select an answer first
18foundation · easy
Which R function removes rows with missing values from a data frame?
Select an answer first
19foundation · easy
Which R function is most appropriate to read a tab-delimited text file into a data frame?
Select an answer first
20application · easy
A data frame `patients` has a column `blood_pressure` with some missing values. An analyst wants to count how many missing values are in that column. Which R expression gives the count?
Select an answer first

Finished these 5 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to DATA-SCIENCE-FOUNDATIONS

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by Dell Technologies. “DATA-SCIENCE-FOUNDATIONS” is a trademark of its owner, used for identification only.

Explain How Basic R Commands Are Used to Initially Explore and Analyze the Data DATA-SCIENCE-FOUNDATIONS Practice Questions (Page 4)

Questions 16–20

A data file `data.txt` uses tabs as separators and has a header row. An analyst wants to load it into R and then check the structure of the resulting data frame. Which sequence of commands is correct?

A data frame `students` has a column `grade` that contains values like 'A', 'B', 'C', and 'D'. An analyst wants to treat this column as a categorical variable with a fixed set of levels. Which R function is most appropriate to convert this column?

Which R function removes rows with missing values from a data frame?

Which R function is most appropriate to read a tab-delimited text file into a data frame?

A data frame `patients` has a column `blood_pressure` with some missing values. An analyst wants to count how many missing values are in that column. Which R expression gives the count?

Keep studying — Initial Analysis of the Data