Learn French: L'étude a confirmé le résultat, donc c'est un fait. - The study confirmed the result, therefore it is a fact.

Yes, you could use alors (so), but donc (therefore) is perfect here. Donc emphasizes a direct, logical consequence. Since a study logically leads to a result, donc sounds very natural and slightly more formal. Alors would also work but is slightly more casual.

Why does it say c'est un fait instead of il est un fait?

In French, you must use c'est (it is) when it is followed by a noun that has an article (like un, le, or mon). Because we are saying un fait (a fact), c'est is the required choice. You would only use il est if an adjective stood completely alone.

L'étude is feminine, so why doesn't the past tense verb confirmé have an extra 'e' at the end?

Because this past tense uses the helping verb avoir (a). When using avoir, the past participle (confirmé) doesn't change to match the subject (L'étude). It only changes if the direct object comes before the verb.

Do I pronounce the 't' at the end of fait?

Yes! When fait is used as a noun meaning 'a fact' in the singular, the final 't' is usually pronounced. Just keep in mind that in the plural (des faits), both the 't' and 's' are silent.