Board Thread:General Discussion/@comment-24438583-20140123220050/@comment-24145588-20140214185435

Both right. :-) Each attempt is independent of all previous, so on any single attempt, the chance is 0.01. But the cumulative expectation of having at least one success is given by:

1.00 - (chance of that many consecutive failures)

Which is the same as:

1.00 - (chance of a failure on a single attempt) raised to (the number of attempts)

In the more familar case of coin flips, with a 0.50 chance of success or failure on each attempt, it would be:

1 attempt: Chance of failure: 0.50; Chance of success: 0.50.

2 attempts: Chance of two failures: 0.50 * 0.50 = 0.25; Chance of at least one success: 0.75

3 attempts: Chance of three failures: 0.50 ^ 3 = 0.125; Chance of at least one success: 0.875.

Etc. Now, change it to Ethereal breeding, with the presumed 0.99 chance of failure and 0.01 chance of success on each attempt:

1 attempt: Chance of failure: 0.99; Chance of success, 0.01.

2 attempts: Chance of two failures: 0.99 * 0.99 = 0.9801; Chance of at least one success: 0.0199.

3 attempts: Chance of three failures: 0.99 ^ 3 = 0.970299; Chance of at least one success: 0.029701.

And as Auttheum posted:

29 attempts: Chance of 29 failures: 0.99 ^ 29 = 0.74717; Chance of at least one success: 0.25283.

69 attempts: Chance of 69 failures: 0.99 ^ 69 = 0.49884; Chance of at least one success: 0.50116.

138 attempts: Chance of 138 failures: 0.99 ^ 138 = 0.24984; Chance of at least one success: 0.75016.

But as PurpleMonsterMama correctly points out, no matter how many times you try, your previous attempts have (or should have) no effect on your next attempt. If you flip a coin and get heads 10 times in a row (unlikely, but it happens) it doesn't in any way increase the chances of getting tails the next time.

So, although you probably can't go on getting failed attempts forever, your next attempt is never any more likely than any single prior attempt. Which is why the Wishing Torches are so darned popular.