articles - When there are some words between 'a' and the corresponding noun, do I use 'an'?

Which sentence is correct?

I performed a reliability analysis.

or

I performed an reliability analysis.

Answer

Your first sentence is correct:

I performed a reliability analysis.

The choice between a and an has nothing to do with the noun. It is entirely dependent on the sound that comes after the indefinite article.

a whole hour.

a tropical island.

an honourable solider.

If the next word after the indefinite article starts with a consonant sound, the indefinite article needs to be a.

If the next word after the indefinite article starts with a vowel sound, the indefinite article needs to be an.