# Questions tagged [probability]

This tag is for basic questions about probability and for questions in which one wants to calculate a probability, expected value, variance, standard deviation, or similar quantity. For questions about the theoretical footing of probability (especially using measure theory), please ask under (probability-theory) instead. For questions about specific probability distributions, please use (probability-distributions).

65,705 questions
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### Apex angle of a triangle as a random variable

I am not an expert in Probability Theory and I apologize if I make some mistakes in "translating" the following problem into the language of random variables. Any help also to improve the formulation ...
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### Reflected Brownian motion on a compact interval whose lenght is going to 0

Suppose I have a Brownian motion $X_t$ in the interval $[0, \gamma]$ which is reflected at the boundaries $0$ and $\gamma$. We call $P_\gamma$ the law of such reflected Brownian motion. The generator ...
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### Is “30 times more likely” equivalent to a “3000% greater probability”?

I am trying to make a persuasive point based on facts and would like to be most accurate / clear in my point. Would "30 times more likely" be equivalent to a 3000% greater probability"
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### What is the distribution of $(1+X^2)e^{-X^2/2}$ when $X$ is Cauchy?

If $X$ is a Cauchy random variable with $f(x)=\frac{1}{\pi}\frac{1}{1+x^{2}}$, what is the distribution of $Y= (1+X^2)e^{-X^2/2}$ ? What I tried: I was thinking I may be able to use Jacobian, but I ...
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### probability question on casting a pair of dice

A pair of dice is cast until a seven appears twice or until each of a six and eight has appeared at least once. Show that the probability of the six and eight occurring before two sevens is 0.546. An ...
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### Basic concept of Probability

1.A box contain 10 pairs shoes, if 8 shoes are randomly selected, what is the probability that there will be a. No complete pair b. Exactly one complete pair 2.Twi die are are used, each loaded ...