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Right choice is (a) snames

Easy 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.

The correct answer is (c) Vector

To explain I would say: Vector is a BASIC DATA structure in R that contains an ELEMENT of similar type. These data types in R can be logical, integer, DOUBLE, character, complex and ALSO raw. In R using the function, typeof() one can check the data type of vector.

The correct answer is (b) Equal

The explanation is: The length of a list is equal to the number of components in that list. Lists can be created using the list function. Like data FRAMES, they can INCORPORATE a MIXTURE of modes into the one list and each COMPONENT can be of a different length or size.

Right ANSWER is (d) List

The explanation is: Lists can be created using the list FUNCTION. Like data frames, they can INCORPORATE a mixture of modes into the one list and each component can be of a DIFFERENT length or size.

The CORRECT choice is (c) seq

The best I can explain: 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.

Right answer is (c) Variables

The best I can explain: In R, the variables are not declared as some DATA type. The variables are ASSIGNED with R-Objects and the data type of the R-object will become the data type of the VARIABLE. There are many TYPES of R-objects.

Right option is (B) Rownames()

To explain I WOULD say: Data frames can have additional attributes such as rownames(), which can be useful for annotating data, like subject_id or sample_id. But most of the time they are not used. A data FRAME is an IMPORTANT data type in R.

Right OPTION is (d) Single

To explain I WOULD say: To extract a SUBLIST, we use single BRACKETS. There are a number of ways of ACCESSING the first component of a list.

Correct choice is (b) Rep

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.

Correct answer is (a) Data.frames()

The best explanation: Data frames are tabular data OBJECTS. Unlike a matrix in each data frame every COLUMN will contain different modes of data. Data Frames are CREATED using the data.frame() FUNCTION. It is the list of VECTORS of same length.

The correct answer is (a) Same

The best EXPLANATION: A data FRAME is a very important data type in R. It’s pretty much the de facto data structure for most TABULAR data and what we use for statistics. A data frame was a special type of list in which every element of the list has the same length.

Correct CHOICE is (b) Second

For EXPLANATION I would say: The second dimension corresponds to the EXPLANATORY VARIABLES collected for each species. The THIRD dimension corresponds to the species.

Correct option is (B) Matrix

To EXPLAIN I would say: 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.

The correct OPTION is (b) Array

Easy explanation: The array function takes a dim attribute which CREATES the REQUIRED number of dimensions. While matrices are confined to TWO dimensions, arrays COULD be of any number of dimensions.

Correct option is (b) Same

Easiest EXPLANATION: All columns in a matrix must have the same mode(numeric, character, etc) and ALSO the same LENGTH. byrow=TRUE INDICATES that the matrix should be FILLED by rows. byrow=FALSE indicates that the matrix should be filled by columns (the default).

Right ANSWER is (d) 5

For EXPLANATION: The most BASIC TYPE of R OBJECT is a vector.

Correct choice is (B) Extraction

The best I can explain: There are a number of ways of accessing the first component of a list. We can either access it through the NAME of that component (if names are assigned) or by using a number corresponding to the position the component CORRESPONDS to. The former APPROACH can be performed using subsetting ([[]]) or alternatively, by the extraction operator ($).

Right choice is (a) Typeof()

BEST explanation: In R using the function, typeof() one can check the data type of vector. Vector is a basic data structure in R which contains element of similar type. These data TYPES in R can be LOGICAL, integer, double, character, complex and also RAW.

Correct OPTION is (c) Data types

To elaborate: Based on the data type of a VARIABLE, the OS ALLOCATES the memory and decides what can be STORED on the reserved memory. This means that when you create a variable you RESERVE some space in memory.

Right answer is (b) double

For explanation I WOULD say: This means that EVEN if you see a number like “1” or “2” in R, which you might THINK of as integers, they are likely REPRESENTED behind the scenes as numeric objects something like “1.00” or “2.00”.

Correct OPTION is (a) Name of the component

Best explanation: There are a number of ways of ACCESSING the first component of a list. We can EITHER ACCESS it through the name of that component (if names are ASSIGNED) or by using a number corresponding to the position of the component.

The correct option is (c) Scan

The 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.

The correct ANSWER is (b) Lists

The 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.

Correct answer is (c) DATA sets

Easy explanation: A data frame is more general than a MATRIX, in that different columns can have different modes (numeric, character, factor, etc). This is similar to SAS and SPSS DATASETS. There are many WAYS to identify the elements of a data frame.

The CORRECT answer is (a) SPLINE

The best explanation: There are also many FUNCTIONS within R that produce a list as output. Examples of these functions INCLUDE spline(), density() and locator().Joining two lists can be achieved either using the concatenation FUNCTION or the append function.

Correct choice is (a) Names

The explanation: To determine the names ASSIGNED to a list, the names function can be USED. Lists can be created USING the list function. Like DATA frames, they can incorporate a MIXTURE of modes into the one list and each component can be of a different length or size.

The correct option is (b) Lists

The EXPLANATION: There are also MANY functions WITHIN R that produce a LIST as output. Examples of these functions include spline(), DENSITY() and locator().

Right choice is (a) Ordinal VARIABLE

To elaborate: An ordered factor is used to REPRESENT an ordinal variable. R will treat factors as nominal variables and also ordered factors as ordinal variables in STATISTICAL procedures and GRAPHICAL analyses.

Correct choice is (c) L

To ELABORATE: Entering 1 in R GIVES you a NUMERIC object; entering 1L EXPLICITLY gives you an integer object.

Right option is (a) Number of the position

For EXPLANATION I would say: There are a number of ways of accessing the first component of a list. We can either access it through the NAME of that component (if NAMES are assigned) or by USING a number corresponding to the position the component.

Right answer is (B) Iris

To ELABORATE: The iris DATASET is a three dimensional dataset. ONE dimension is represented for each species: Setosa, Versicolor and Virginica.

Correct choice is (a) Numeric

To explain: Decimal VALUES are REFERRED to as numeric data types in R. Data frames are the tabular data objects. Unlike a matrix in data FRAME every COLUMN can contain different MODES of data.

The correct CHOICE is (C) attributes()

Explanation: Not all R objects CONTAIN attributes, in which case the attributes() function RETURNS NULL.

The correct option is (c) Lists

Explanation: A vector is the most common and basic data STRUCTURE in R. Technically, vectors can be ONE of TWO TYPES of atomic vectors and lists. Although vector most commonly refers to the atomic types.

Right ANSWER is (a) EMPTY vectors can be created with the VECTOR() function

Explanation: A vector can only CONTAIN objects of the same class.

Correct choice is (a) Loops

Easiest explanation: COMPUTATION with vectors is ACHIEVED using an element-by-element operation. This is useful when writing CODE because it AVOIDS ’for loops’.

Correct OPTION is (a) Vector

Explanation: Factors are the r-objects which are CREATED using a vector. It stores the vector with ALSO the distinct values of the elements in the vector as labels. They are USEFUL in statistical modelling.

Correct CHOICE is (a) Spline

The explanation: The spline function returns a list of densities (y) CORRESPONDING to bin values (x). These can be PASSED to the PLOT routine to PRODUCE a line graph of the density.

Correct CHOICE is (a) Concat

The best I can EXPLAIN: JOINING two lists can be achieved EITHER using the concatenation function or the APPEND function.

Correct CHOICE is (c) ARRAYS

Explanation: Arrays are similar to matrices which can have more than two dimensions. See help(array) for details. FACTORS are created using the factor() function. We can Identify ELEMENTS of a list using the [[]] convention.

Right answer is (b) NUMBER INF represents infinity in R

The EXPLANATION: This allows us to represent entities like 1 / 0.

The correct choice is (c) Matrix

For explanation I would say: A matrix is a two-dimensional rectangular DATA set. It can be CREATED USING the vector input to a matrix function. The labels are always character irrespective of whether it is numeric or character and also BOOLEAN etc in the vector.

Correct choice is (a) Subsetting COMMANDS

Best EXPLANATION: To access elements with a value greater than FIVE we can USE some subsetting commands and logical OPERATORS to produce the desired result.

The correct option is (B) Function()

Best explanation: Factors are created using the factor() function. The labels are always CHARACTER irrespective of WHETHER it is numeric or character or also Boolean etc. in the vector. The nlevels functions will give the COUNT of levels.

Correct option is (a) METADATA

The EXPLANATION is: These metadata can be very useful in that they HELP to DESCRIBE the object.