Dholmes0309
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Help it's for a girl and I am over my head
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Harry_the_cat
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Sorry, but is she incapable of asking for herself?
Dr.Peterson
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The question is about 6.16, False positives.
But we really need to know where you need help -- that is, how much do we have to drain the pond so it isn't over your head?
In particular, do you want to use the binomial distribution, or just basic ideas about probabilities?
But we really need to know where you need help -- that is, how much do we have to drain the pond so it isn't over your head?
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In particular, do you want to use the binomial distribution, or just basic ideas about probabilities?
pleasehelp.dontunderstand
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The chances of having no false positives is .081572. There are many ways that I could imagine you are being asked to solve this problem.
Firstly, I hope you recognize that this is the binomial distribution because the number of trials is fixed, all the trials are assumed to be independent, there are two possibilities (success or failure) and the probability of success for each trial is presumed to be equal.
Additionally, successes in probability are just the relevant event occurring (in this case false positives). It does not always reflect a good "successful" thing!
The formula:
P(x) = ((n!)/(n - x)!(x)!)(p^x)q^(n-x)
where...
n = number of trials
x = number of successes desired
p = probability of success
q = 1 - p (probability of failure)
In this situation n would be equal to 500, x would be equal to 0, p would be equal to .005 and q would be equal to .995. Plug in the numbers and see what you get.
Note: in a situation where you would be finding cumulative probability, you would have to add a Σ in front with x on the top and k = 0 on the bottom. But since we are just finding the probability of zero, this is not necessary.
Microsoft Excel:
If you are being asked to do this in excel, you must follow the format below -
binom.dist(number of successes desired, number of trials, probability of success, cumulative or not (true = cumulative, false = not cumulative))
In this problem, you would type in your values as given in the problem. You should use false at the end as you are just finding the probability of zero successes, although using true will give you the same answer in this case because you can't find the probability of anything less than zero.
Your final command should look like...
= binom.dist(0, 500, .005, false)
I know many schools and other institutions of learning (including my own) use coding, specifically python, to teach statistics. If this is your situation, I would be happy to explain it!
Firstly, I hope you recognize that this is the binomial distribution because the number of trials is fixed, all the trials are assumed to be independent, there are two possibilities (success or failure) and the probability of success for each trial is presumed to be equal.
Additionally, successes in probability are just the relevant event occurring (in this case false positives). It does not always reflect a good "successful" thing!
The formula:
P(x) = ((n!)/(n - x)!(x)!)(p^x)q^(n-x)
where...
n = number of trials
x = number of successes desired
p = probability of success
q = 1 - p (probability of failure)
In this situation n would be equal to 500, x would be equal to 0, p would be equal to .005 and q would be equal to .995. Plug in the numbers and see what you get.
Note: in a situation where you would be finding cumulative probability, you would have to add a Σ in front with x on the top and k = 0 on the bottom. But since we are just finding the probability of zero, this is not necessary.
Microsoft Excel:
If you are being asked to do this in excel, you must follow the format below -
binom.dist(number of successes desired, number of trials, probability of success, cumulative or not (true = cumulative, false = not cumulative))
In this problem, you would type in your values as given in the problem. You should use false at the end as you are just finding the probability of zero successes, although using true will give you the same answer in this case because you can't find the probability of anything less than zero.
Your final command should look like...
= binom.dist(0, 500, .005, false)
I know many schools and other institutions of learning (including my own) use coding, specifically python, to teach statistics. If this is your situation, I would be happy to explain it!