If I want to save a plot to a PDF file, which of the following is a correct way of doing that?
A. Construct the plot on the screen device and then copy it to a PDF file with dev.copy2pdf()
B. Construct the plot on the PNG device with png(), then copy it to a PDF with dev.copy2pdf()
C. Open the PostScript device with postscript(), construct the plot, then close the device with dev.off()
D. Open the screen device with quartz(), construct the plot, and then close the device with dev.off()
Answer: Option A
This Question Belongs to R Programming >> Data Manipulation With Dplyr
In dplyr, what function is used to select specific columns from a data frame?
A. select_cols()
B. choose_cols()
C. select()
D. pick()
How do you filter rows in a dplyr data frame based on a specific condition using filter()?
A. filter_rows()
B. row_filter()
C. filter_conditions()
D. filter()
In dplyr, what does the arrange() function do?
A. Sorts the data frame in ascending order
B. Arranges the columns in a specified order
C. Orders the rows based on a specific column
D. Sorts the data frame in descending order
What function is used to create a new variable in a dplyr data frame based on existing variables?
A. create_var()
B. mutate()
C. new_variable()
D. add_column()
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