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Discussion Starter #1
Hi all,

I'm needing a statistics whizz to help me out with a question.

What I want to know is the cumulative probability of two non exclusive events

Specifically:

if I shoot Weapon X and Weapon Y at a target and Weapon X has 30% chance of causing a wound and Weapon Y has a 10% chance of causing a wound; how do I calculate the overall percentage chance of at least one wound being caused?

Is it as simple as 30 + 10 = 40 ?
 

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Yes.

You are overthinking it.

The only time it gets complex is when you add multiple non linear percentages.
 

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OK thanks for that, just checking to be sure.

For shits and giggles what are multiple non linear percentages as it might apply to 40k ?
 

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OK thanks for that, just checking to be sure.

For shits and giggles what are multiple non linear percentages as it might apply to 40k ?
Ok an example would be, if you have a 1/7 X 4 then add it with a 8/19 X 3 and then add them or find some correlation.

Also I mistyped I should have wrote, multiple non-linear fractions, but since fractions can be converted into percentages its kinda the same thing.

In relation to Warhammer 40k, one example of this would be. If you have 6 shots that each hit on a 4+ (50%) then you roll a scatter die for each, how many shots would hit right on target.

So for this you would have to combine, a 1/2 with a 1/3. And find out how many times they both succeed.
 

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Is it as simple as 30 + 10 = 40 ?
No.

The easiest way to do one or more of two independent events is to work out neither happening.

Chance X misses = 7/10
Chance Y misses = 9/10

Therefore chance both miss = 7/10 x 9/10 = 63/100

Therefore chance at least one hits = 37/100, i.e. 37%
 

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Discussion Starter #8
aaaaa I'm so confused.

3 say it equals 40 and one says "almost 40" lol
 

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Just realized from Magpie's location that (s)he is a vashta nerada.

Also, I made a 50% in stats because the university passed everyone and fired the prof. I say you have a 50/50 shot, as it's either going to happen, or it's not.
 

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Dave is correct. If you have 3 40% chances of something happening it's not 120%.

It's 1-((6/10)*(6/10)*(6/10)) = 0,784 = 78,40% chance.

I always used to think that my guardians with conceal and fortune had a 3++ save, and was dissatisfied every time I didn't manage to save 66% of my boys. Then I learned better.
 

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Discussion Starter #11
Now that is making more sense, I could never work out how it ended up being odds greater than one !
 
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