Question

Exercise 1.1. Predict the result of the following R statements. Explain the reason ing behind the results a exp(-Inf) b. NA ==NA c. NA ==NULL d. NULL == NULL e. NA & FALSE

Answer 1

ANSWER:

GIVEN THAT

  

1 .The result of the following R statements :

a) exp(-Inf)

        Result: 0

• This is because exp(-Inf) = 1/exp(Inf) = 1/Inf, which is equal to 0. Here, Inf = \infty .

(b) NA==NA

Result: NA

• NA means missing data, so since we are checking whether NA is equal to NA, we also get NA, since we have no information about it.

(c) NA==NULL

Result: logical (0)

• NULL is an empty object and NA is a logical value indicating missing data. So, when we are checking their equivalence, we get back an empty object, since we are not getting any response.

(d) NULL==NULL

Result: logical (0)

• When we are checking the equivalence of 2 empty objects, we are getting back an empty object.

(e) NA & FALSE

Result: FALSE

• Both NA and FALSE are logical values, but since they denote 2 different things, there is no common characteristic between them.
• Hence, we are getting back FALSE.