Explain How Basic R Commands Are Used to Initially Explore and Analyze the Data DATA-SCIENCE-FOUNDATIONS Practice Questions (Page 2)

Questions 6–10

1. 6application · easy

   A CSV file `sales_data.csv` has a header row and uses commas as separators. An analyst wants to load it into R and then check the first few rows. Which sequence of commands is correct?

   • Asales <- read.table('sales_data.csv'); head(sales)
   • Bsales <- read.csv('sales_data.csv'); head(sales)
   • Csales <- read.delim('sales_data.csv'); head(sales)
   • Dsales <- read.csv2('sales_data.csv'); head(sales)
   Reveal Solution Discussion Select an answer first
2. 7application · medium

   After loading a data frame `data`, an analyst wants to see the last few rows and also check for missing values in the entire data frame. Which two commands would accomplish this?

   • Ahead(data) and summary(data)
   • Bstr(data) and complete.cases(data)
   • Ctail(data) and is.na(data)
   • Dtail(data) and any(is.na(data))
   Reveal Solution Discussion Select an answer first
4. 8foundation · easy

   Which R data structure is best suited for storing a collection of named attributes of different types (e.g., a customer's name, age, and purchase amount) as a single unit?

   • AA list
   • BA matrix
   • CA factor
   • DA vector
   Reveal Solution Discussion Select an answer first
5. 9foundation · easy

   Which R function returns a logical vector indicating which elements of a vector are missing (NA)?

   • Ana.omit()
   • Bis.na()
   • Ccomplete.cases()
   • Dsummary()
   Reveal Solution Discussion Select an answer first
6. 10application · easy

   A data frame `cars` has columns `speed` and `distance`. An analyst wants to explore the relationship between speed and distance. Which R command is most appropriate?

   • Aplot(cars$speed, cars$distance)
   • Bboxplot(cars$speed, cars$distance)
   • Csummary(cars)
   • Dhist(cars$speed)
   Reveal Solution Discussion Select an answer first