1. Which of the following function is used for quantiles of quantitative values?
a) quantile
b) quantity
c) quantiles
d) all of the mentioned
Explanation: In probability and statistics, the quantile function specifies, for a given probability in the probability distribution of a random variable, the value at which the probability of the random variable will be less than or equal to that probability.
2. Which of the following function is used for determining missing values?
a) any
b) all
c) is
d) all of the mentioned
Explanation: In R, missing values are represented by the symbol NA.
3. Point out the wrong statement.
a) Common variables are used to create missingness vector
b) Common variables are used to cutting up quantitative variables
c) Common variables are not used to apply transforms
d) All of the mentioned
Explanation: Common variables are not used to apply transforms.
4. Which of the following transforms can be performed with data value?
a) log2
b) cos
c) log10
d) all of the mentioned
Explanation: Many common transforms can be applied to the data with R.
5. Each observation forms a column in tidy data.
a) True
b) False
Explanation: Each variable forms a column in tidy data.
6. Which of the following function is used for casting data frames?
a) dcast
b) ucast
c) rcast
d) all of the mentioned
Explanation: Use acast or dcast depending on whether you want vector/matrix/array output or data frame output.
7. Which of the following join is by default used in plyr package?
a) left
b) right
c) full
d) all of the mentioned
Explanation: Join is faster in plyr package.
8. mutate function is used for casting as multi dimensional arrays.
a) True
b) False
Explanation: mutate is used for adding new variables.
9. Which of the following function is good for the automatic splitting of names?
a) split
b) strsplit
c) autsplit
d) none of the mentioned
Explanation: strsplit split a character string or vector of character strings using a regular expression or a literal string.
10. Point out the correct statement.
a) gsub is used for fixing character vectors
b) sub is used for finding values like grep
c) grep is used for fixing character vectors
d) none of the mentioned
Explanation: sub and gsub is used for fixing character vectors.