For the determiner in English, I learn that they are used in many different situations. For example, a is used before a noun. However, sometimes I misuse it. Therefore, I would like to understand it, so I can write my sentence correctly.
I have a vector of random variables.
As I understand, a in this sentence is a determiner used to identify the vector, not the random variables. Hence, it is correct to say:
Let X be a vector of random variables.
Because in this sentence, the determiner a refers to the vector X and did not refer to the random variables. Is that correct? if not, then, why?
However, similar to this sentence, I would like to specify the dimension of this vector. So, is it ok to say:
Let X be an n-dimensional vector of random variables.
Or I must not use the determiner an here because n-dimensional is plural in its meaning. Is that correct?
So, which sentence is correct?