All Questions
Tagged with probability probability-theory
115
questions
30
votes
8
answers
26k
views
Distributed probability random number generator
I want to generate a number based on a distributed probability. For example, just say there are the following occurrences of each numbers:
Number| Count
1 | 150
2 | ...
- 493
18
votes
3
answers
4k
views
Probability of Outcomes Algorithm
I have a probability problem, which I need to simulate in a reasonable amount of time. In simplified form, I have 30 unfair coins each with a different known probability. I then want to ask things ...
- 183
8
votes
2
answers
20k
views
Expected collisions for perfect 32bit crc
I'm trying to determine how my crc compares to an "ideal" 32bit crc.
So I ran my crc over 1 million completely random samples of data and collected the amount of collisions, I want to compare this ...
- 3,865
8
votes
1
answer
17k
views
Calculating Probability of a Random Variable in a Distribution in Python
Given a mean and standard-deviation defining a normal distribution, how would you calculate the following probabilities in pure-Python (i.e. no Numpy/Scipy or other packages not in the standard ...
- 63k
7
votes
4
answers
16k
views
How to create a probability by a given percentage?
I'm trying to create a percentage-based probability for a game. E.g. if an item has a 45% chance of a critical hit, that must mean it is 45 of 100 hits would be critical.
First, I tried to use a ...
- 75
7
votes
2
answers
14k
views
Probability notation [closed]
I want to ask you about the notation in probability.
I know that
P(A | B) = the conditional probability that event A occurs given that
event B has occurred already
But I cannot find what A,B ...
- 401
6
votes
0
answers
2k
views
Flip a probability tree in R
Currently taking a course on decision analysis. There is a concept called "flipping a probability tree", illustrated in the following example.
May I know:
(1) Is there a way to do the above ...
- 869
4
votes
2
answers
116
views
JS inverting probabilities
I'm generating a grid of objects, each of which has one of 3 colors. Assume I'm filling a particular grid cell. I know that around this cell there are, for example, 1 object of color 0, 1 of color 1 ...
- 3,395
4
votes
0
answers
350
views
How to obtain the probability distribution of a sum of dependent discrete random variables more efficiently
I hope you are well. I was wondering if you could help me with the question provided in the attached link, please. Below the link I attach an R-code that solves the problem recursively for particular ...
- 329
4
votes
0
answers
67
views
How could time series prediction be applied in a real-time setting where it is infeasible to track every single item?
The problem: Find the estimated lifetime of an object (e.g. the time it is written next) or the corresponding PDF. This is known as a renewal process.
Constraint: it is infeasible to track metadata ...
- 701
3
votes
3
answers
390
views
Batch scripting Issues with random, probability or a bug
Please excuse any mistakes, this is my first post! Recently I was bored and was trying to make a batch script clone of an arcade game I once saw:
http://antikrish.com/2013/01/28/whittakers-ascot-gold-...
- 61
3
votes
1
answer
665
views
How to Make a Uniform Random Integer Generator from a Random Boolean Generator?
I have a hardware-based boolean generator that generates either 1 or 0 uniformly. How to use it to make a uniform 8-bit integer generator? I'm currently using the collected booleans to create the ...
- 130
3
votes
1
answer
417
views
Should Naive Bayes multiple all the word in the vocabulary
I am using Naive Bayes in text classification.
Assume that my vocabulary is ["apple","boy","cup"] and the class label is "spam" or "ham". Each document will be covered to a 3-dimentional 0-1 vector. ...
3
votes
2
answers
563
views
Multiple ngrams in transition matrix, probability not adding to 1
I'm trying to find a way to make a transition matrix using unigrams, bigrams, and trigrams for a given text using python and numpy. Each row's probabilities should equal to one. I did this first with ...
- 162
3
votes
1
answer
196
views
How to decompose efficiently dpoibin into its summands in R?
The Poisson-Binomial distribution concerns the probability of the number of successes in a sequence of independent Bernoulli trials with different probabilities of success. This is a generalization of ...
- 329
2
votes
3
answers
4k
views
how to implement non uniform probability distribution?
I am trying to implement non-uniform probability distribution in genetic algorithm.
In the implementation of genetic program, I have an experiment which has 3 outcomes, where each outcome has ...
- 1,630
2
votes
2
answers
1k
views
How to get random number with each number has its own probability [duplicate]
For example, I want to get random number from set S = {0, 1, 2, 3}. But instead of each number has same probability to shown (which is 25%), now I have different probability for each number, let say {...
- 3,784
2
votes
1
answer
128
views
Simulating a dice throw with threadlocalrandom does not converge to the expected value
I was trying to verify the expected value formula in java.
I did something very trivial, I simulated the roll of a dice, but I mapped each side to a specific value. So each value has probability of 1/...
- 4,109
2
votes
1
answer
945
views
Birthday paradox in DataBase (calculate collision probability)
According to Birthday paradox:
If i apply it to the Database (please correct me if I'm wrong):
if we need to store UNIQUE hashed data in Database and we have a hash algorythm that can generate 365 ...
- 2,660
2
votes
3
answers
2k
views
Computationally simple pseudo-Gaussian distribution with varying mean and standard deviation?
This picture from Wikipedia has a nice example of the sort of functions I'd ideally like to generate:
Right now I'm using the Irwin-Hall Distribution, which is more or less a polynomial approximation ...
- 13.6k
1
vote
4
answers
8k
views
How to obtain a value based on a certain probability
I have some functions which generate double, float, short, long random values. I have another function to which I pass the datatype and which should return a random value. Now I need to choose in that ...
- 521
1
vote
2
answers
818
views
Calculate current probability in respect to prior probabilities to get uniform distribution
Disclaimer: not sure if title of question is accurate...
Let's say I need to wash the dishes within the next 100 minutes. I know I MUST do it after 100 minutes as the latest. I ask myself every 2 ...
- 8,715
1
vote
1
answer
3k
views
How to implement the standard normal cumulative distribution function in C (or other language)
First of all, for those of you who don't know this law, don't be afraid it's actually pretty simple.
On this link http://en.wikipedia.org/wiki/Black%E2%80%93Scholes_model you will see this law from a ...
- 463
1
vote
1
answer
474
views
Draw random numbers from a custom probability density function in Matlab
I want to sample R random numbers from a custom probability density function in Matlab.
This is the expression of the probability density function evaluated at x.
I thought about using ...
- 2,259
1
vote
1
answer
1k
views
gaussian mixture model probability matlab
I have a data of dimension 50x100000. (100000 features, each has a dimension of 50).
I would like to fit a gaussian mixture model using this data. I used the following code.
obj = ...
- 3,440
1
vote
1
answer
1k
views
Simulating computation of the expected value of random variable Y
I have been given the following task:
Compute the expected value of Y=e^{-X}(X is uniform between 0 and 1) with a simulation in R. Plot the expected value as a function of the number of simulations ...
1
vote
1
answer
118
views
How to get this probability outcome in R?
New to R. Not sure how to go about this problem. Essentially I want to create a Monte Carlo simulation. However this is how it's supposed to go:
There are only 3 people (A,B,C) And only come into ...
- 417
1
vote
1
answer
7k
views
How to generate independent identically distributed (iid) random variables in python
I am developing a simulation infrastructure with some random events (for instance, sources that generate output with a certain probability). So far I've been doing it using the random.random() ...
- 675
1
vote
1
answer
131
views
Calculate probability of an event not by exclusion
I have some doubt with these kind of problems, example:
"If we asked 20,000 in a stadium to toss a coin 10 times, what it's the probability of at least one person getting 10 heads?"
I took ...
- 881
1
vote
2
answers
781
views
If Random variable is a function
The basic definition of random variable is that it is a function based on random experiment.the question is that if it is a function say f then how can it take numerical values..
Suppose if ...
- 11
1
vote
1
answer
61
views
a function display logarithm of a pdf in matlab
I need to calculate the density of 50 in a standard normal distribution, actually, the result will return to 0 by pdf('norm',50,0,1), then I try to display the logarithm of it,it doesn't work with log(...
- 59
1
vote
2
answers
182
views
Multiple Chi Square Test on a factor with two levels and multiple parameters in a function
Issue
I have a group called Country that has two levels (Spain and Germany) and I have nine parameters that are measurements taken from spectrograms for dolphin whistles. I want to determine if any of ...
- 1,033
1
vote
1
answer
65
views
Match Bayesian Networks using Joint Probablity to Network Graph
I'm stuck on a task right now. Given the Joint Probabilities given below, how can I show that they belong exactly to one of the networks (and not to the other two). According to my intuition I would ...
- 91
1
vote
1
answer
320
views
Finding Probability on a biased die
I had to simulate a biased die such that 6 occurs more than 50% of the times. Which I was able to do using:
from random import randint,choice
def bdie():
out = random.randint(0,2)
if (out==1 ...
- 364
1
vote
1
answer
122
views
Shiny App on Evolutionary Dynamics: Simulation Errors?
I’m a math grad student who has just started learning R, and I could really use some help from any R-literate people!
I’m building a shiny app that models probabilistic evolutionary behavior (as a ...
1
vote
2
answers
141
views
Reservoir Sampling unable to understand probability
To make clear following is the question:
Given an input stream of an indeterminate length, how do you return a random member of that stream (with equal probability for each), given that you're not ...
1
vote
2
answers
44
views
Can i trust on a key generation process without check for duplicates?
I'm using a process to put a name on user profile images and i'm afraid of collisions.
The name pattern that i'm using is the following:
9999999_9999999_9999999
So the images are named like:
...
- 397
1
vote
0
answers
48
views
Issue regarding Triangular Distribution Function calculation
The daily demand for gasoline in a metropolitan area is best modeled according to the Triangular distribution between 1.25 million and 2.05 million gallons, and with a peak (mode) of 1.85 million ...
- 31
1
vote
0
answers
37
views
Calculating Probability of Earthquakes in a Four-Week Period Using Poisson Distribution in Octave
Question: In an area of a country, it is known that earthquakes occur 1.4 times in 8 days in an average sense since the dawn of history. However, there were 15 earthquakes in the last four
weeks. ...
- 11
1
vote
0
answers
54
views
How to get a new solution with high probability from previously found, incomplete solutions with different probabilities?
I am working on a AI algorithm. first when program runs a random solution is generated from which ,in first iteration of the program 10 solution vectors are created, by analyzing these solutions we ...
- 9
1
vote
1
answer
255
views
probability for winning combination in poker game
We are trying to calculate probabilities(and odds) for "bet on poker" game on which we are working now.
To calculate probabilities and odds for each hand we used https://github.com/cookpete/poker-odds ...
- 314
1
vote
0
answers
34
views
How to decide which Probability distribution to use on a specific problem?
Which probability distribution i can use to understand the number of orders one person can handle in a company? It's like each person has orders which takes minimum of 50 days to complete and no limit ...
- 59
1
vote
0
answers
61
views
R Probability calculation with number of Criterion
I have historic data with 4 constraints say C1, C2, C3 and C4 . All the constraints take string value.
If we take an example of a football match say 4 constraints would be
C1 :place where game is ...
- 11
1
vote
1
answer
2k
views
Find probability of the given data set, what probability i can say it is bad
I have a issue where there is a data set. and in there i have good and bad category, and in that category there are few elements that can be good and bad....
you can see the ven diagram i attached ...
1
vote
1
answer
194
views
reservoir sampling understanding probaility
I am having trouble understanding the probabilities involved in reservoir sampling. Below is the sample code which I have seen used in almost everywhere:
1/*
2 S has items to sample, R will ...
- 936
0
votes
4
answers
428
views
I don't understand Bayes' rule [closed]
I know that Bayes' rule is in form of P(A/B)=P(B/A)*P(A)/P(B)
What I don't understand is, what means P(A/B) and P(B/A) ?
Regards.
- 517
0
votes
2
answers
266
views
Calculate probability that a baby is right handed
A doctor says that a baby who predominantly turns his/her head to the right while lying on his/her back will be right-handed and conversely one who predominantly turns to the left will be left-handed. ...
- 297
0
votes
3
answers
204
views
code for choosing N values with some associated probabilities
Suppose we have a set x of N values {x_i; i=1,...,N} and a set of some associated probabilities {w_i; i=1,...,N}.
We want to get from the set x, a new set x^ of N values {x^_i; i=1,...,N} by ...
- 5,206
0
votes
3
answers
3k
views
Probability of occuring of An infinitely often
IF probability of occurance of A , infinitely often is 0, does it mean probability of occurance of A complement , infinitely often is 1???
- 2,069
0
votes
1
answer
501
views
Compute probability of union of n events from array
I have a PHP array containing N probabilities (of N different events). So it looks like:
$events = [0.85, 1, 0, 0.15, 0.49, 1, 1, 0, 0, 0.59, 0.93]
where each value in the array is the probability ...
- 1,038