Q1. How does a matrix differ from a data frame?

A matrix may contain numeric values only.
A matrix must not be singular.
A data frame may contain variables that have different modes.
A data frame may contain variables of different lengths.

Q2. What value does this statement return?

unclass(as.Date(“1971-01-01”))

1
365
4
12

https://www.videosprofitnetwork.com/watch.xml?key=0552df4fd7e4a0cf0843c17c23524c5b

Q3. What do you use to take an object such as a data frame out of the workspace?

remove()
erase()
detach()
delete()

Q4. Review the following code. What is the result of line 3?

xvect<-c(1,2,3)
xvect[2] <- “2”
xvect

[1] 1 2 3
[1] “1” 2 “3”
[1] “1” “2” “3”
[1] 7 9

Related article: Semrush Amazon Seller Certification Answers

Related article: 5 Best Freelance Jobs Bookkeeping from Home 2023

Q5. The variable height is a numeric vector in the code below. Which statement returns the value 35?

height(length(height))
height[length(height)]
height[length[height]]
height(5)

Q6. In the image below, the data frame is named rates. The statement sd(rates[, 2]) returns 39. As what does R regard Ellen’s product ratings?

sample with replacement
population
trimmed sample
sample <– not sure

Q7. Which choice does R regard as an acceptable name for a variable?

Var_A!
\_VarA
.2Var_A
Var2_A

Q8. What is the principal difference between an array and a matrix?

A matrix has two dimensions, while an array can have three or more dimensions.
An array is a subtype of the data frame, while a matrix is a separate type entirely.

A matrix can have columns of different lengths, but an array’s columns must all be the same length.
A matrix may contain numeric values only, while an array can mix different types of values.

Q9. Which is not a property of lists and vectors?

type
length
attributes
scalar

Q10. Which function displays the first five rows of the data frame named pizza?

BOF(pizza, 5)
first(pizza, 5)
top(pizza, 5)