# R Programming Questions and Answers – Data Types – 6

This set of R Programming Questions & Answers for Exams focuses on “Data Types – 6”.

1. The four most frequently used types of data objects in R are vectors, matrices, data frames and ________
a) Function
b) Lists
c) Packages
d) Interfaces

Explanation: The four most frequently used types of data objects in R are vectors, matrices, data frames and lists. A list is a generalisation of a vector and represents a collection of data objects.

2. A __________ is a set of elements appearing in rows and columns where the elements are of the same mode whether they are logical, numeric (integer or double), complex or character.
a) Vector
b) Matrix
c) Lists
d) Data frames

Explanation: A matrix is a set of elements appearing in rows and columns where the elements are of the same mode whether they are logical, numeric (integer or double), complex or character.

3. What is the simplest way of creating the vector?
a) C function
b) Create
c) Destroy
d) Invalid

Explanation: The simplest way to create a vector is through the concatenation function, c. This function binds elements together, whether they are of character form, numeric or logical.

4. Which function replicates elements of vectors?
a) C
b) Rep
c) Crep
d) Grep

Explanation: The rep function replicates elements of vectors. The seq function creates a regular sequence of values to form a vector. The four most frequently used types of data objects in R are vectors, matrices, data frames and lists.

5. The ________ function creates a regular sequence of values to form a vector.
a) sequel
b) Rep
c) seq
d) Grep

Explanation: The rep function replicates elements of vectors. The seq function creates a regular sequence of values to form a vector. The four most frequently used types of data objects in R are vectors, matrices, data frames and lists.

6. Which function is used to enter in data at the terminal?
a) Scanned
b) Scnn
c) Scan
d) Sccn

Explanation: The scan function is used to enter data at the terminal. This is useful for small datasets but tiresome for entering in large datasets.

7. Computation with vectors is achieved using an element-by-element operation for avoiding _________
a) Loops
b) Functions
c) Packages
d) Interfaces

Explanation: Computation with vectors is achieved using an element-by-element operation. This is useful when writing code because it avoids ’for loops’.

8. To bind a row onto an already existing matrix, the ______ function can be used.
a) Rbind
b) Sbnd
c) Gbind
d) Sbind

Explanation: To bind a row onto an already existing matrix, the rbind function can be used. The scan function is used to enter data at the terminal.

9. Which of the following is a 3-dimensional dataset?
a) Eris
b) Iris
c) Toris
d) Iris

Explanation: The iris dataset is a three dimensional dataset. One dimension is represented for each species: Setosa, Versicolor and Virginica.

10. Which dimension corresponds to the explanatory variables collected for each species?
a) First
b) Second
c) Third
d) Fifth

Explanation: The second dimension corresponds to the explanatory variables collected for each species. The third dimension corresponds to the species.

11. Using the ________ vector, we create a species factor and bind it to the columns of iris.df.
a) snames
b) rnames
c) jnames
d) fnames

Explanation: Using the Snames vector, we create a species factor and bind it to the columns of iris.df. The iris dataset is a three dimensional dataset.

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