What is the value of y in this code?

x <- NA
y <- x/1

Elementary commands in R consist of either _______ or assignments.

The variable height is a numeric vector in the code below. Which statement returns the value 35?

How does a matrix differ from a data frame?

What statement shows the objects on your workspace?

What is the output of getOption(“defaultPackages”) in R studio?

How to name rows and columns in DataFrames and Matrices F in R?

If a command is not complete at the end of a line, R will give a different prompt, by default it is ____________

Functionality of R is divided into a number of __________

Review line 1 below. What does the statement in line 2 return?

1 mylist <- list(1,2,"C",4,5)
2 unlist(mylist)

Two variable in the mydata data frame are named Var1 and Var2. How do you tell a bivariate function, such as cor.test, which two variables you want to analyze?

What do you use to take an object such as a data frame out of the workspace?

What is the principal difference between an array and a matrix?

unclass(as.Date("1971-01-01"))

What function joins two or more column vectors to form a data frame?

What is the value of names(v[4])?

v <- 1:3
names(v) <- c("a", "b", "c")
v[4] <- 4

What is the function to set row names for a data frame?

R files has an extension ______

What does c contain?

a <- c(3,3,6.5,8)
b <- c(7,2,5.5,10)
c <- a < b

Review the following code. What is the result of line 3?

xvect<-c(1,2,3)
xvect[2] <- "2"
xvect

A data frame named d.pizza is part of the DescTools package. A statement is missing from the following R code and an error is therefore likely to occur. Which statement is missing?

library(DescTools)
deliver <- aggregate(count,by=list(area,driver), FUN=mean)
print(deliver)

ournames is a character vector. What values does the statement below return to Cpeople?

Cpeople <- ournames %in% grep("^C", ournames, value=TRUE)

Which of the following is default prompt for UNIX environment?

A single element of a character vector is referred as ________

_____ text editor provides more general support mechanisms via ESS for working interactively with R.

Advanced programmers can write ______ code to manipulate R objects.

d.pizza is a data frame. It's column named temperature contains only numbers. If u extract temperature using the [] accessors, its class defaults to numeric. How can you access temperature so that it retains the class of data.frame?

> class( d.pizza[ , "temperature" ] )
> "numeric"

Point out the wrong statement?

You accidentally display a large data frame on the R console, losing all the statements you entered during the current session. What is the best way to get the prior 25 statements back?

Which of the following statements doesn't yield the code output below. Review the following code. What is the result of line 3?

x <- c(1, 2, 3, 4)
Output: [1] 2 3 4

Which of the following will start the R program?

Given DFMerged <- merge(DF1, DF2) and the image below, how manu rows are in DFMerged?

DF1(data frame 1): DF2(data frame 2):
VarA VarB VarA VarD
1 1 2 1 18 21
2 4 5 2 19 22
3 7 8 3 20 23

Review the statements below. Does the use of the dim function change the class of y, and if so what is y's new class?

> y <- 1:9
> dim(y) <- c(3,3)

The most convenient way to use R is at a graphics workstation running a ________ system.

If the code is stored in the external file, which of the following function is used to call them to a working directory?

Which of the following statement is alternative to _________?

solve

Which is not a property of lists and vectors?

How many atomic vector types does R have?

Which function displays the first five rows of the data frame named pizza?

How does a vector differ from a list?

What is mydf$y in this code?

mydf <- data.frame(x=1:3, y=c("a","b","c"), stringAsFactors=FALSE)

Which choice does R regard as an acceptable name for a variable?