R Language quiz questions

R Language interview questions

  • 1.

    ______ is used to view all packages installed.

    1. library()

    2. search()

    3. .libPaths()

    4. All of the mentioned

    Answer
  • 2.

    _________ is used to convert wide data to long data.

    1. melt

    2. dcast

    3. cast

    4. None of the mentioned

    Answer
  • 3.

    ______ specializes in converting data from wide to long format.

    1. gcc

    2. reshape

    3. reshape2

    4. All of the mentioned

    Answer
  • 4.

    Which of the following is a library for statistical quality control. ?

    1. gcc

    2. qcc

    3. anc

    4. All of the mentioned

    Answer
  • 5.

    __________ modifies geom/stat aesthetic defaults for future plots

    1. translate_qplot_base

    2. translate_qplot_gpl

    3. translate_qplot_defaults

    4. translate_qplot_ggplot

    Answer
  • 6.

    Which of the following is similar to Moment.js ?

    1. stringr

    2. lubridate

    3. ploy

    4. All of the mentioned

    Answer
  • 7.

    Which of the following syntax is used to install forecast package ?

    1. install.pack(“forecast”)

    2. install.packages(“cast”)

    3. install.packages(“forecast”)

    4. All of the mentioned

    Answer
  • 8.

    ________ provides needed string operators in R.

    1. str

    2. forecast

    3. stringr

    4. All of the mentioned

    Answer
  • 9.

    ________ makes it incredibly easy to fit time series models like ARIMA, ARMA, AR, Exponential Smoothing, etc.

    1. sqldf

    2. plyr

    3. forecast

    4. All of the mentioned

    Answer
  • 10.

    ______ splits a data frame and results an array (hence the da). Hopefully you’re getting the idea here.

    1. apply

    2. daply

    3. stats

    4. All of the mentioned

    Answer
  • 11.

    ______ let’s you perform SQL queries on your R data frames.

    1. sqldf

    2. plyr

    3. forecast

    4. All of the mentioned

    Answer
  • 12.

    Which of the following will add the title “R language” to the graph ?

    1. titleAdd( “R language”)

    2. title( “R language”)

    3. titleBar( “R language”)

    4. var(x, na.rm=TRUE)

    Answer
  • 13.

    Which of the following function is used for plotting histogram ?

    1. hist()

    2. histog()

    3. histg()

    4. All of the mentioned

    Answer
  • 14.

    Which of the following sets the size of the outer margins for the graph ?

    1. par(mfrow=c(nrow,mcol))

    2. par(ask=TRUE)

    3. par(omi=c(0,0,1,0) )

    4. All of the mentioned

    Answer
  • 15.

    Which of the following finds row sums for each level of a grouping variable ?

    1. as.numeric(x)

    2. rowsum(x, group, reorder = TRUE, …)

    3. as.order(x)

    4. colSums (x, na.rm = FALSE, dims = 1)

    Answer
  • 16.

    Which of the following may be used for linear regression ?

    1. X %*% Y

    2. solve(A)

    3. solve(A,B)

    4. All of the mentioned

    Answer
  • 17.

    which of the following statement tells the row with the minimum value for every column ?

    1. which.min(x)

    2. which.max(x)

    3. z=apply(x,1,which.min)

    4. All of the mentioned

    Answer
  • 18.

    Which of the following statement finds the maximum for each column ?

    1. apply(x,2,max)

    2. col.max(x)

    3. which.min(x)

    4. which.max(x)

    Answer
  • 19.

    Which of the following statement applies the function (FUN) to either rows (1) or columns (2) on object X ?

    1. apply(x,1,min)

    2. apply(x,2,max)

    3. col.max(x)

    4. apply(X, MARGIN, FUN, …)

    Answer
  • 20.

    Which of the following finds row sums for each level of a grouping variable ?

    1. rowSums (x, na.rm = FALSE, dims = 1)

    2. colMeans(x, na.rm = FALSE, dims = 1)

    3. rowMeans(x, na.rm = FALSE, dims = 1)

    4. rowsum(x, group, reorder = TRUE, …)

    Answer

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