Mathematics Stack Exchange
Mathematics Stack Exchange

Questions tagged [probability-distributions]

Questions on using, finding, or otherwise relating to probability distributions, probability density functions (pdfs), cumulative distribution functions (cdfs), or other related functions. Use this tag along with the tags (probability), (probability-theory) or (statistics).

Any probability distribution, including beta, binomial, chi, Erlang, gamma, geometric, lognormal, negative binomial, normal (Gaussian), Pareto, Poisson, Student's t, uniform, Wald, Weibull, zeta, and Zipf.

28080 questions
0
votes
1 answer

uniform distribution

the speed V is uniformly distributed in the range of [V_min,V_max]. Then d(t) is a distance function of the random variable V as given in the equation d(t)=V *t The question: what is the distribution function of…
user 123
  • 7
0
votes
1 answer

Which Conditions Describe the Connection Between Poisson and Binomial Distributions?

From binominal distribution if $n\to\infty$, $p\to 0$ and $n\cdot p=\lambda$ where λ constant then binominal approaches poisson distribution. How can I define in typical form the above three conditions?
Alexander Gotses
  • 1
0
votes
1 answer

Exponential distribution practical problem

In a room, a lamp must be constantly turned on. As soon as it stops working, it is immediatly switched for a new one. Suppose that the lifetime of a lamp can be approximated by an exponetial distribution with average lifetime of 5 days. How many…
user2345678
  • 2,885
0
votes
1 answer

Detecting power-law distribution number of inlinks

I am studying for an exam at university and trying to understand how I can find out if the distribution of inlinks to a page is a power-law WITHOUT knowing the actual number of inlinks. The question that was asked last year is something like: You…
Ninjabin
  • 1
0
votes
1 answer

How to calculate $E(E(X|Y))$ given conditional and marginal pdfs?

I have worked out $f_X(x),f_Y(y),f_{X|Y}(x|y) \ \text{and} \ f_{Y|X}(y|x)$ I wish to verify that $E(E(X|Y))=E(X)$ For $E(X)$ I will be calculating: $$\int_{I_x}xf_X(x) \ dx$$ and for $E(E(X|Y))$ I am not so sure, but currently I think:…
An Invisible Carrot
  • 420
0
votes
1 answer

What is the joint probability mass function?

A pond has $r$ red fish, $b$ blue fish, and $g$ green fish. Let $R$ be the number of red fish, $B$ be the number of blue fish, and $G$ be the number of green fish in a random sample size of $N$. What is the joint probability mass function of $R$,…
John Hoffman
  • 2,734
0
votes
1 answer

Geometric distribution expected value

A and B take alternate turns at kicking a football. Their probability of scoring the goal are $p_1$ and $p_2$ respectively. The first scorer allows the second one more kick. If the other scores, the game is drawn otherwise the first kicker wins. A…
mathnoob123
  • 1,373
0
votes
0 answers

distance distribution between two points using their length distribution

I have a circle with radius x which is a random variable that its distance from the center of circle has a known pdf. Now suppose we have an other point y (in which it may be in the circle or outside) that again its distance from the center of the…
Simin
  • 1
0
votes
1 answer

what is distribution of a partial sample of 5 boys and 5 girls

If you have a group of 5 boys and 5 girls and you take a random sample of 5 what is the distribution of results of number of boys 0,1,2,3,4,5? If you had a very large equal number of boys and girls it would be the binomial distribution. How would…
RMR
  • 1
0
votes
2 answers

Probability Distribution - Discrete Maths

A string consisting of $A$s, $B$s and $C$s is chosen uniformly at random from the set $\{BBBBB, ABBBC, AACCC, ABBCC, BBBBC \}$. Let $X$ be the number of $A$s in the string. Give the probability distribution of $X$. Do i assume $X$ as the number of…
Dave Kumar
  • 39
0
votes
1 answer

Counter intuitive result attained in a mixed type radom variable exercise

Suppose that we toss a fair coin. If a head $H$ comes up, we roll a fair dice; otherwise we choose a random number in the interval $(0,10)$. Let $X$ be the number observed. If the value observed was equal to $2$, give the probability that we…
user2345678
  • 2,885
0
votes
1 answer

Probability density function of $Y=\exp(X)$ and $Y=\sqrt{X}$

If X has uniform distribution on (0,1), how do I calculate probability density functions of $Y=\exp(X)$ and $Y=\sqrt{X}$? I can assume the shape of these pdfs when I make histogram of mentioned variables in MATLAB, but i don't know how to calculate…
Emir
  • 105
0
votes
1 answer

If X and Y follow Geometric Distribution, which distribution will X-Y follow?

Please help. I have to find out conditional distribution for X given X-Y=n where X and Y are independent random variables representing the no. of failure preceeding the first success.
Rajat Rautela
  • 1
0
votes
1 answer

Are values in a probability density function related to standard deviation?

Hard to fit the whole question in the title. I'm struggling to intuitively grasp probability density functions, but I hope I'm on to something here. Is it correct of me to say that, when dealing with normally distributed data, the (y) value…
miroli
  • 103
0
votes
1 answer

Probability question, exponentially distributed with rate one

Currently struggling with this question: Have no idea where to start. This is for my probability course. Assume that the time between emissions from a radioactive source are independent and exponentially distributed with rate one. Each of these…
Jason Huang
  • 11
1 2 3
…
99 100