data is a plural form
datum is singular

hmm okay.
so police is singluar right? Those collective nouns which has group of people are singular but collective nouns like data which do no involve people is plural?

Also,
A group of students --> is singular or plural --> in either case why?
The majority of students ---? Is singular or plural --? in either case why?

the book I am reading, it has former plural and later singluar, I just can't figure out why is it so. Is it because of "A" and "The"

MTariq wrote:hmm okay.
so police is singluar right? Those collective nouns which has group of people are singular but collective nouns like data which do no involve people is plural?

Also,
A group of students --> is singular or plural --> in either case why?
The majority of students ---? Is singular or plural --? in either case why?

the book I am reading, it has former plural and later singluar, I just can't figure out why is it so. Is it because of "A" and "The"

I think we need to assess whether the object of the preposition is singular or whether it is plural.
In this case, the object is "students", which is plural. Thus, I believe we'd need a corresponding plural verb.

The majority of students are maintaining a 'B' average or better.

On the other hand, if the object of the preposition is singular, we'd adjust our verb accordingly.

The majority of the museum is currently under construction.

I'm obviously not an instructor, so take all this with a grain of salt. This is merely how I see it.