38 posts tagged with math and probability.
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Too Many Strata To Sample

I have multiple independent variables that I want to stratify my sampling across, but the result would be way more strata than I can sample. Is there a way to stratify across different character states for each independent variable without creating strata for the interactions of each? Example inside. [more inside]
posted by agentofselection on Sep 21, 2016 - 6 answers

Can you figure out the probability of a specific outcome?

I work in a field where we think about possibly dangerous people. If Mr. X is a poor driver and has a 5% chance of running a red light in the next month, can you know the probability of him running a red light at a specific intersection? Can you know a range of probabilities for that specific intersection? What if it's the intersection that he drives through most often? I think this likely has an easy answer but none of us can clearly explain it so we keep talking about it.
posted by kerf on Sep 11, 2016 - 6 answers

Statistical framing of the engineering and extremism article

Reading this article on the blue got me thinking about conditional probabilities, prediction and causality. I came up with an analytical framing of what I think the article is saying and would be grateful if stats/social science Mefites could tell me if it seems accurate or else set me right. [more inside]
posted by mister_kaupungister on Mar 25, 2016 - 3 answers

How to Math

I'm a computer science major in college. I'm not a freakin' genius, but I do well-- get A's in my classes, good with abstraction (e.g. pointers), etc. However, I seem to have missed... my entire high school pre-Calculus math curriculum? I don't know. [more inside]
posted by anonymous on Aug 14, 2015 - 13 answers

Probability distributions and their practical applications

I am looking for a resource that lists probability distributions and their common real-world applications. For example, I'd expect to see: Lognormal - daily returns in the stock market. Poisson - failure rates for mechanical equipment, ... [more inside]
posted by wivy on Feb 19, 2015 - 6 answers

Math Problem

Please help with this probability related math problem. [more inside]
posted by BeaverTerror on Dec 4, 2014 - 9 answers

2 problems of combinations and permutations.

How many unique ways are there to put X rocks into Y boxes? (Given two different sets of attributes for both the rocks and the boxes.) [more inside]
posted by CustooFintel on Jun 4, 2014 - 18 answers

Chance of event with small sample size, based on larger related sample?

Can/how can one improve the estimate for a chance of an event with a small historical sample size by utilizing the chance of a related event with a large historical sample size? Example and half-assed guess inside. [more inside]
posted by Flunkie on Mar 20, 2014 - 16 answers

The Gambler's Fallacy, of course. But maybe...

A coin flips three times and comes up heads 2/3. Not suspect. But a coin flips 100,000 times and comes up heads 2 out of 3 times, that starts to look fishy. The standard probability of this is always roughly 50-50, but assuming a 2/3 ratio pointing to a "rigged" coin, how could you plot the increasing likelihood that a given coin is rigged? [more inside]
posted by ASoze on Jan 8, 2014 - 17 answers

Bad at math

I have a question about probability math. I am essentially flipping a coin (except instead of a 50/50 chance, my odds are 50.5% heads, 49.5% tails). I am concerned with the probability of me hitting heads (a 50.5% chance) several times in a row. [more inside]
posted by disillusioned on Dec 25, 2013 - 42 answers

Probability and a rather unique deck of cards.

Each card in a certain deck has three letters on it. The first letter is either A, B, or C. The second letter is either D, E, F, or G. The third letter is either H, I, J, K, or L. Every possible combination is represented exactly once in the deck. Ergo, there are 3x4x5=60 cards in the deck. How can I determine the probability that a hand of X cards, drawn randomly from the deck, will include at least one of each of the letters?
posted by CustooFintel on Nov 2, 2013 - 32 answers

What does a professional statistician do?

(Good) jobs involving probability and statistics other than math teacher or actuary? [more inside]
posted by CustooFintel on Dec 3, 2012 - 15 answers

How to solve a complex statistics problem with a script?

In this game, you roll a number of six-sided dice to get a total. The total is either the highest single die result, or the sum of any multiples rolled, whichever is higher. For example: If I roll three dice and get a 3, 4, and 6, my total is 6. But if I roll a 4, 4, and 6, my total is 8, the sum of the two 4s. What I want to find out is the mean, median, mode, and standard deviation of the possible totals given N dice. How might I create a simple script to compute this? [more inside]
posted by j0hnpaul on Nov 30, 2012 - 24 answers

Practice Probability Word Problems

What great books or resources are there for practicing probability word problems such as for standardized tests like the GRE? [more inside]
posted by Mr. Papagiorgio on Nov 8, 2012 - 3 answers

What are the odds that two randomly selected people share the same bank PIN?

Statisticsfilter: Given available information about the distribution of self-selected 4-digit passwords (specifically banking PINs), is it possible to calculate the probability of two randomly selected individuals having the same PIN? If so, what're the odds? [more inside]
posted by myrrh on Oct 27, 2012 - 15 answers

How do I calculate the probability of a specific sum of repeated die rolls?

I'm looking to learn how to calculate probabilities for a multi-round dice game. I've researched this question some, and it looks like I might need to know how to use the multinomial distribution, but I can't find any good introductions. Please point me to the most layman-accessible educational material on this subject, and help me to help myself. [more inside]
posted by Richard Daly on Sep 28, 2012 - 6 answers

Gambling odds question

How would one (legally) take advantage of the change in odds of a given NFL team to win the Super Bowl? [more inside]
posted by glenngulia on Sep 24, 2012 - 6 answers

What are the odds?

Math/probability not sports: I am not a gambler, but I am trying out a method of betting on sports with some initial success. At what point can I use the numbers to confidently assume that this is down to the system rather than luck? [more inside]
posted by cincinnatus c on Sep 19, 2012 - 4 answers

Thirsty work

Mathfilter. Bonus: involves football and beer [more inside]
posted by raider on Jan 12, 2012 - 22 answers

Probability Question

Probability Question [more inside]
posted by nickhb on Sep 3, 2011 - 15 answers

Need help with a probability question

Can someone help with a probability question? [more inside]
posted by caroljean63 on Jun 25, 2011 - 22 answers

Straightforward Dice Probability

Please refresh my memory with regard to a straightforward question of fair dice and probability. [more inside]
posted by Justinian on Jan 20, 2011 - 14 answers

Help me learn to figure out dice probability for games

Help me teach myself enough about probability to properly balance the board game I want to design. [more inside]
posted by Caduceus on Aug 9, 2010 - 3 answers

Conditional Probability

Stats-filter: Given a binary matrix, if I know the total number of ones in a given row and a given column, can I calculate the probability that a given position contains a one? [more inside]
posted by chrisamiller on Dec 16, 2009 - 25 answers

How many songs do I have to listen to before I start again?

Can you help me figure out this math question related to probability? [more inside]
posted by jacquilynne on Dec 12, 2009 - 41 answers

Teach me about this thing you call "math"...

Here's an obnoxious school question that's been nagging me for days: Suppose that the height (at the shoulder) of adult African bull bush elephants is normally distributed with µ = 3.3 meters and ∂ = .2 meter. The elephant on display at the Smithsonian Institute has a height 4 meters and is the largest elephant on record. What is the probability that an adult African bull bush elephant has height 4 meters or more? [more inside]
posted by incomple on Dec 8, 2009 - 8 answers

Math and Odds and Blackjack

What are the chances, in blackjack, that I will start with 15, and the dealer will be showing a 10 (or face card worth 10)? [more inside]
posted by gummo on Oct 28, 2008 - 8 answers

Probability question (in need of code)

It's late, I'm tired, and I have a probability and coding question that's fairly simple. [more inside]
posted by chrisamiller on Aug 13, 2008 - 10 answers

How to calculate probability of being dealt certain cards?

You're dealt 8 cards face down from a 52 card deck. All values are determined by the number on the card, not the suit. What is the probability of each card being dealt? [more inside]
posted by b_thinky on Jul 9, 2008 - 12 answers

complex dice probability make head esplode

I need a tool to help me analyze the probability of certain events occurring regarding a pool of X dice for a game I am creating. See my examples below. [more inside]
posted by DetonatedManiac on Dec 21, 2007 - 7 answers

How many rolls 'till n values in a row.

Given a fair die with s sides, what is the expected number of rolls r before I get o outcomes with the same value v in a row? [Note this is emphatically NOT a homework problem; I just really want to know, feel like I should be able to figure it out, can't, and it is driving me nuts.] [more inside]
posted by lucasks on Dec 19, 2007 - 30 answers

Infinite vs Infinite

ProbabilityFilter: Calling all mathematicians... [more inside]
posted by 777 on Nov 21, 2006 - 26 answers

Looking for help with a question of probability.

MathFilter: Okay, I've got this gumball machine, which contains an infinite amount of gumballs, evenly distributed between 100 different flavors... [more inside]
posted by rifflesby on Sep 1, 2006 - 10 answers

Binomial distribution comparison

Probability of one binomially-distributed variable being greater than another one - is there a closed form for this? [more inside]
posted by wanderingmind on May 25, 2006 - 11 answers

Deriving formulas for Weibull distributions

Probability: A coworker is having an issue with deriving a few formulas for a Weibull distribution. Any pointers? [more inside]
posted by TommyH on Nov 7, 2005 - 2 answers

In probability, is it good practice to always guess the smallest possible number of elements for a given draw? Can it be solved? Is there a name for the theory addressing it, if so?

Probability question (more...) [more inside]
posted by trharlan on Jan 24, 2005 - 16 answers

What are the odds of finding 20 needles in 270 haystacks?

Suppose there are 20 objects hidden in a collection of 270 haystacks. What are your odds of searching 100 haystacks (assuming that if you choose to search a haystack with an object in it, you'll find that object) without finding an object? My discrete math skillz have eroded to the point where any attempt to work this out myself yields preposterous numbers..
posted by COBRA! on Dec 1, 2004 - 30 answers

Probability calculations

If the likelihood of event A occurring is 15%, and the likelihood of independent event B occuring is 5%, what is the likelihood of EITHER event occuring? [more inside]
posted by sohcahtoa on Sep 10, 2004 - 12 answers

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