R Programming Practice Test 6

1. ____________ function can be used to select the random sample of size ‘n’ from a huge dataset.

Simple()

Sample()

Signal()

While()

2. Which function basically finds the intersection between two different sets of data?

Swap

Delegate

Merge

Converge

3. What will be the output of the following R code?

> printmessage <- function(x) {
+ if(x > 0)
+         print("x is greater than zero")
+ else
+         print("x is less than or equal to zero")
+ invisible(x)
+ }
> printmessage(NA)

Messages

Null

Warning

Error

4. _________ require you to pass a function whose argument is a vector of parameters.

opm()

opt()

optimize()

optimise()

5. Write a function to extract the first name in the string “Mrs. Jake Luther”?

Substr

Return

Substi

Substring

6. ______________ measures the probability of the binary response variable in R language.

Statistics

Simpler Regression

Logical Regression

Multivariate Regression

7. Which function is used to select variables and observations from a given dataset?

Subset()

While()

Signal()

Sample()

8. Point out the wrong statement?

The scoping rules of a language determine how values are assigned to free variables

An environment is a collection of (symbol, value) pairs, i.e. x is a symbol and 3.14 might be its value

Dynamic scoping turns out to be particularly useful for simplifying statistical computations

Lexical scoping turns out to be particularly useful for simplifying statistical computations

9. What will be the output of the following R code?

> nLL <- make.NegLogLik(normals, c(1, FALSE))
> optimize(nLL, c(1e-6, 10))$minimum

1.217775

empty

1.800596

3.73424

10. What would be the value of following R expression?

 log(-1)

Warning in log(-1): NaNs produced

Null