R Interview Questions – Set 02

by

Explain the doBy package?

This package is used to define the desired table using function and model formula.

Give names of those packages which are used for data imputation.

There are the following packages which are used for data imputation

  1. MICE
  2. missFores
  3. Mi
  4. Hmisc
  5. Amelia
  6. imputeR

Explain S3 and S4 systems.

In oops, the S3 is used to overload any function. So that we can call the functions with different names, and it depends on the type of input parameter or the number of parameters, and the S4 is the most important characteristic of oops. However, this is a limitation, as it is quite difficult to debug. There is an optional reference class for S4.

Differentiate between library() and require() functions.

If the desired package cannot be loaded, then the library() function gives an error message and display while the required () function is used inside the function and throws a warning message whenever a particular package is not found.

Differentiate between R and Python in terms of functionality?

For data analysis, R has inbuilt functionality, but in Python, the data analysis functionalities are not inbuilt. They are available by packages like Pandas and Numpy.

Explain Histogram.

A histogram is a type of bar chart which shows the frequency of the number of values which are compared with a set of values ranges. The histogram is used for the distribution, whereas a bar chart is used for comparing different entities. In the histogram, each bar represents the height of the number of values present in the given range.

Differentiate between qda() and lda() function.

The qda() function prints a quadratic discriminant function while lda() function print the discriminant functions based on the centered variable.

What will be the output of the expression all(NA==NA)?

[1] NA

Explain leaps() function.

The leaps() function is used to perform the all-subsets regression and defined under the leaps package.

Explain the use of the table() function.

This function is used to create the frequency table in R.