Calculate video game item drop chance

[VivaLaFisica]

Hello. I’m playing a game in which an item drops with 8 unique properties. Those properties each have an equal chance to be randomly picked from a pool of 25. Of the 8 properties on the item, I’m looking for a specific 4. So what’re the odds that in the 8 chances of assigning each property that 4 of the ones I’m looking for will appear out of the potential 25? The order is not important. Thank you.

 

[R.M.]

By "odds" do you mean "probability"? They are not the same thing, so please clarify what you are looking for.

 

[ImMAD]

I think he means probability from context. That would be 4/25*3/25*2/25*1/25*(8c4) = 4!/25^4*70 = 0.0043 or in around every 233 trials.

 

[VivaLaFisica]

I think he means probability from context. That would be 4/25*3/25*2/25*1/25*(8c4) = 4!/25^4*70 = 0.0043 or in around every 233 trials.

Thank you. For what it’s worth, I’ve seen this item around 90 times, but at most, with only 3/4 properties I’m hoping for. I suppose this is completely in the real of expectancy…

 

[VivaLaFisica]

By "odds" do you mean "probability"? They are not the same thing, so please clarify what you are looking for.

You’re right. I’m actually interested in both. So if the probability of the item existing is 0.0043, when could I anticipate encountering the item? After so many tries?

 

[ImMAD]

Thank you. For what it’s worth, I’ve seen this item around 90 times, but at most, with only 3/4 properties I’m hoping for. I suppose this is completely in the real of expectancy…

Well, the odds of getting the item with 3 of the 4 properties is around 8.6% compared to 0.43%, so on average you will find the item with 3 properties 20 times as much.

 

[VivaLaFisica]

Well, the odds of getting the item with 3 of the 4 properties is around 8.6% compared to 0.43%, so on average you will find the item with 3 properties 20 times as much.

Mind sharing how you calculated the odds?

 

[Steven G]

Hello. I’m playing a game in which an item drops with 8 unique properties. Those properties each have an equal chance to be randomly picked from a pool of 25. Of the 8 properties on the item,

Are you saying that the 8 unique properties each have an equal chance to be randomly picked from a pool of 25 and the other 17 may have a different chance or each of the 25 have the same chance?

 

[VivaLaFisica]

Are you saying that the 8 unique properties each have an equal chance to be randomly picked from a pool of 25 and the other 17 may have a different chance or each of the 25 have the same chance?

All 25 properties have an equal chance to be selected.
And as for the 3/4 properties probability, is the calculation 3/25*2/25*1/25*(8c3)? That’s approximately 0.0215, which isn’t the 8.6% @ImMAD quoted. Please explain. Thank you.

 

[ImMAD]

Yeah, so you do 4/25*3/25*2/25*(8c3), because you don't have any preference for which of the four properties you get