Stocks/mutual funds: how are dividend payouts calculated?

Factual Questions
1

I have an array of mutual funds to which I made several contributions last year. Looking at the year-end statements, I see that several of them generated dividend payments. It got me to wondering, how are such dividend payouts calculated? Obviously your payment is proportional to your share of ownership, but do they measure your share of ownership based on:

-the exact number of shares you own at the present moment,

-the average number of shares over the period of time between this dividend payout and the previous payout,

-some other method?

2

It’s based on the exact number of shares you held on the Date of Record associated with the dividend payout. That is, “for every share you own on date <X>, you will receive $<D> per share. This money will be paid to you by the company on date <Y>”.