probability distribution

  1. X

    Probability distribution of all possible combinations

    Hi to everybody! I would ask an advice on an analysis that I want to do. I have n=69 balls, within 69, 17 are black balls, 29 white balls, 22 red balls and 1 yellow balls. How can I compute a probability distribution of all possible combinations in r=7 positions, considering that could...
  2. E

    Quantile prediction?

    Here is my situation. I am trying to predict the 'entire' distribution of the dependent variable, not just the mean( or conditional mean). Does it then make sense to seprateley predict quantiles of this variable to learn about the new predicted CDF? I intend to use this CDF as one input (say...
  3. H

    How to determine distribution with no parameters

    I'm confused by this question and I was hoping for some guidance some one to point me in the right direction Let X1.........Xn be a random sample from a population with mean μ, that is E(Xi)=μ for all 1≤i≤n. Define Yi=1 if Xi<μ and Yi=0 otherwise a) Determine the distribution of...
  4. C

    Class Distribution, Boosted Models (gbm) Probability Scores

    All, Problem: I need help to better understand the probability scores that come from the result of a decision tree model. Specifically, I'm using the gbm package from R to create Generalized Boosted Regression Models, but the results I see are common across various ensemble classification...
  5. N

    Tomographic map of 3D data with a dimension described by probability distribution

    I have a three dimensional data set. Two first components are the exact values of(X,Y) and for the third dimension I have a probability attached to each point for each given value of z between (0,1.5). for example P(x0,y0,z0)=0.24 and the probability is not necessarily Gaussian, it can be...
  6. R

    Help with Probabilistic Modeling with many elements in simulation with unknown probs.

    I'm wanting to create a probabilistic model based on several simulations, where I have a binary outcome (go or no-go) and a variable input. The old way of formulating the proability distribution was a straight-forward, curve-fitting of the input variable versus the "go or no-go" outcomes...
  7. S

    Finding the probability distribution of a dataset

    Hello, I have a dataset of 100 numbers. The numbers seem to be random. I wanna find the probability distribution of the dataset. How can I do it mathematically? I would really appreciate a reply. Thank you Sujeeth Kumaravel
  8. A

    Proof the sum of two CDF's is a CDF.

    This is a question my instructor asked in the last midterm exam but nobody was able to solve and he's suggesting it may come out again in the finals: If F(x) and G(X) are two CDF's, prove that H(X) is also a CDF if H(X) = F(X)+G(X)-F(x)G(X) He said something about right...
  9. Y

    Mean of Current I with Random variable of R

    Hi all, I am new to probability and not so good at it, So please bear with me :) If a voltage e is connected across a resistor whose resistance is random variable R, and uniformly distributed between a and b, I needed to find the Mean of current "I" given by "I = e/R" My question...
  10. 1

    Risk Averse

    A store has enough employees to attend to customers that are flowing into it at an average rate of 25 per hour. Should the store manager be employing more people if he expects 32 people per hour, when he is risk-averse and cannot take more than 10% risk?
  11. V

    Weibull distribution for data with zero's

    Hi, Can any one tell me how to fit some data with zero's to a weibull fit using Matlab. I tried using Maximum Likelihood Estimator and wbfit. But I am experiencing problem because of zero's. It requires positive values. Thank you very much Vinay
  12. L

    Conditional Probability Help.

    Helloooo Statisticians! I have a question that I believe I can solve but somehow I'm not getting the correct answer. So I'd really appreciate if anyone can point out my mistake for me. The question is: The grades of 1st year students were analysed. 70% of the top one quarter of the 1st year...
  13. S

    Sampling from a distribution

    Assume I have a distribution governing the possible outcome from a single random variable X. This is something like [0.1, 0.4, 0.2, 0.3] for X being a value of either 1, 2, 3, 4. Is it possible to sample from this distribution, i.e. generate pseudo random numbers upon each of the possible...
  14. H

    Combining probability distribution functions

    Hi, I'm comparing different measurement methods. I listed and derived an equation for each error component per measurement method and calculated the probability distribution using the Monte-Carlo method (calculating each error 300.000 times assuming a normal distribution of the input...
  15. C

    Probability of irregular 10-sided die

    I've got an odd question here: I've got a 10-sided die with sides labeled as such: -1, 0, 0, 0, 0, 1, 1, 1, 1, 2 Thus, the odds for a single die look like this: Odds of -1: 0.1 Odds of 0: 0.4 Odds of +1: 0.4 Odds of +2: 0.1 I'm trying to find the probabilities of rolling every possible outcome...
  16. I

    needs urgent help in probability distribution

    0 down vote favorite Suppose there are 1 million parts which have 1% defective parts i.e 1 million parts have 10000 defective parts. Now suppose we are taking different sample sizes from 1 million like 10%, 30%, 50%, 70%, 90% of 1 million parts and we need to calculate the probability of...
  17. W

    Sampling from N data points based on a given probability distribution

    I have N data points, and each data points is associated with a probability. The sum of the N probabilities equals to one. I need to sample these N data points based on the given probability vector. Are there any algorithms that can allow me to do this kind of sampling?
  18. N

    I'm confused on probability density functions - please help!!

    These questions are from a sample test, I don't know how to do them. Obviously there's a lot of questions so I'm not expecting people to do them for me, just telling me HOW to do them would be amazing. Any help would be extremely appreciated! 1) If P(X) = P(Y), the random variables X and Y are...
  19. K

    Properties of Sample Proportions

    A city council is considering drafting legislation related to the exclusion of renters with children. Since implementation will be expensive, they will only consider proceeding if the true proportion of apartments that prohibit children is more than 75 percent. Suppose that out of 125 sampled...
  20. M

    sampling - distribution of sample mean

    How do I solve this? I'm a little confused by the question itself too. A student's performance is equally good in both subjects. The marks she might be expected to score in each subject may be treated as independent observation drawn from a normal distribution with a mean of 45 and standard...