I'm studying probability with Ross's textbook. In 4.9 EXPECTED VALUE OF SUMS OF RANDOM VARIABLES, the textbook says that
We can interpret the hypergeometric as representing the number of successes in $n$ trials, where trial $i$ is said to be a success if the $i$th ball selected is white. Because the $i$th ball selected is equally likely to be any of the $N$ balls and thus has probability $m/N$ of being white, it follows that the hypergeometric is the number of successes in $n$ trials in which each trial is a success with probability $p = m/N$. Hence, even though these hypergeometric trials are dependent, it follows from the result of Example 9d that the expected value of the hypergeometric is $np = nm/N$.
But I'm wondering why the ith ball selected is equally likely to be any of the N balls. Because I'm not a native speaker, I'm confused what does ith ball selected means exactly and why it becomes equally likely in spite of the fact that trials are dependent.
Thanks for everyone, in advance.