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Random math question for you

raz

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Okay. I'm completing an action 5 times. Each time I complete the action, it has a 50% chance of having the result that I want. My goal is to achieve the desired result twice. What is the percentage chance that that I will achieve the desired result twice after completing the action 5 times?
 

Qre:us

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Nov 21, 2008
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Binomial Probability: P(X = 2) = 0.3125 thus, multiply by 100 = 31.25% chance
Cumulative Probability: P(X < 2) = 0.1875
Cumulative Probability: P(X < and/or = 2) = 0.5
Cumulative Probability: P(X > 2) = 0.5
Cumulative Probability: P(X > and/or = 2) = 0.8125

Edit: am I doing your homework for you? :thelook:
 

Prototype

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Why?
No replies!...Are people afraid of being wrong?... I want to say 33% off the top of my head..
 

runvardh

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only twice, or at least twice?
 

raz

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Binomial Probability: P(X = 2) = 0.3125 thus, multiply by 100 = 31.25% chance
Cumulative Probability: P(X < 2) = 0.1875
Cumulative Probability: P(X < and/or = 2) = 0.5
Cumulative Probability: P(X > 2) = 0.5
Cumulative Probability: P(X > and/or = 2) = 0.8125

Edit: am I doing your homework for you? :thelook:

No. You're not doing my homework. Let me elaborate on why the question is here. It's taken from Pokemon actually. I've been playing it a lot lately, and been doing a lot of things that are just left up to doing something over and over relying on probability. I was doing something today and it sparked some curiosity.

I'm breeding Pokemon in the game. They have a nature attribute that I care a lot about. There are 25 possible natures, and with certain conditions, you can raise the possibility of it having the nature you want to 50%. So, I'm sitting here hatching Pokemon eggs over and over again until I have a certain amount of Pokemon I want with the nature that I want. If I have 5 Pokemon eggs and I only need 2 of them to have the nature I want, but each one has a 50% chance to have it, what is the chance of me having 2 Pokemon of the nature I want after hatching all 5 eggs?

There's where the question originated. :)
 

redacted

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Okay. I'm completing an action 5 times. Each time I complete the action, it has a 50% chance of having the result that I want. My goal is to achieve the desired result twice. What is the percentage chance that that I will achieve the desired result twice after completing the action 5 times?

I'm assuming more than 2 times is okay too.

So you're basically asking for 1 minus the chances that it will happen 0 times or 1 time.

chances it will happen exactly 1 time: 5*1/2^5 = 5/32
chances it will happen 0 times: 1/2^5 = 1/32
chances it won't happen 1 or 0 times: 1-(5/32+1/32) = 26/32

i think.
 

runvardh

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At least twice you're looking at 4 occurances out of 6 possible outcomes, so around 66 or 67%.
 

redacted

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At least twice you're looking at 4 occurances out of 6 possible outcomes, so around 66 or 67%.

huh?

There are 32 possible sequences of 5 coin flips (which is equivalent to what he's talking about). One of those sequences has 0 heads. Five of them have 1 heads. The rest have two or more heads. 81.25%
 

raz

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Have none of you people done Finite/Statistics in highschool? This is highschool level bullshit.


Binomial probability - Wikipedia, the free encyclopedia

Mathwords: Binomial Probability Formula

Quit in 8th grade sir and have a GED. Furthest math I've done so far in college is intermediate Algebra. Wait, so did we have an answer? Explain it for us newbies, please. :D I'll check back tonight after work. I was actually curious about this because it became annoying after I'd hatch like 5 eggs, and none of them had the nature I wanted. :p
 

The_Liquid_Laser

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Cumulative Probability: P(X > and/or = 2) = 0.8125

This is correct.

I'm assuming more than 2 times is okay too.

So you're basically asking for 1 minus the chances that it will happen 0 times or 1 time.

chances it will happen exactly 1 time: 5*1/2^5 = 5/32
chances it will happen 0 times: 1/2^5 = 1/32
chances it won't happen 1 or 0 times: 1-(5/32+1/32) = 26/32

i think.

So is this.

Prototype said:
I just needed an excuse for my weak math skills...lol... When I look at numbers I see letters.

What? When you see an X you think that is a letter? Everyone knows that X is a number lol. :D
 
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