Question

Question 1 1 pts If vv - list(a-1,b-2) why doesn't as.vector(vv) work to coerce vw to an atomic vector? Not applicable: The code returns an error. vv is already a vector atomic vectors cannot have named elements elements of an atomic vector must be of the same type. Question 2 2 pts Suppose ll<-list(a-1,b-c(2,3)). How do we replace the value 3 with the missing data code NA? 0 11[[2]][2] <-NA ﹁ ll <-as.na(II[[2]]) 0 ll[[22]] <-NA is.na([211) <-2

Answer 1

Answer 1

vv is already a vector

(option 2)

A list is implicitly still a vector. Thus, when you type in as.vector(vv), it remains a vector, and the data type does not change.

Answer 2

ll[[2]][2]= NA

(option 1)

When referencing to an element of a list, double square brackets have to be used. Thus, by typing this code we are saying that we need to change the 2nd element (by typing [2]) of the 2nd element of the list (by typing [[2]])

Answer 3

2,5

(option 3)

Since we are binding the matrices by columns, the number of rows of both the matrices must be the same (which they are, in our case). Thus, the combined matrix will have shape 2,5 (2 rows and 5 columns).

Answer 4

Not applicable: The code returns an error

(option 1)

The number of columns must be same to combine the matrices by rows (which they are not, in our case). Thus, the matrices cannot be combined.

Answer 5

vv[1] is inserted into A[2,1], then vv[2] into A[1,2], then vv[1] into A[2,2].

(option 1)

The elements of a matrix are modified column wise (down the columns). Thus, this is the correct answer.

If you have any doubts/ questions/ feedback related to any of the answers, please feel free to comment and I shall get back to you. Happy learning!