distribution

  1. B

    Sum of n random variables with normal distribution

    I am struggling with this problem: Independent random variables X_1, ... , X_n have normal distribution with mean 0 and variance 2. What is the distribution of random variable: X_1 + ... + X_n ? I know that the sum od two random variables with normal distribution has normal distribution as...
  2. K

    What type of distribution is this and am I being sensible?

    I have a computer model, which I need to run 3500 times with different input parameters. The model's accuracy depends on a constant, let's call it T, which unlike the input parameters doesn't change between model runs. By decreasing T, the model's accuracy improves but the computational cost...
  3. trinker

    Link function for proportional outcome

    I have a data set where the outcome variable is percent passing (ELA and Math tests) for school districts. I will use a 2 level multilevel model with various predictors/covariates at level one and two. The outcome variable is percent passing. Obviously the outcome is limited to between 0...
  4. G

    Fieller-Hinkley Ratio of Correlated Random Variables: Question On Applying Theory

    I am a senior in college writing a thesis analyzing and critiquing government income transfer programs, such as SNAP (food stamps). Here is my issue. I am using data collected from the consumer expenditure survey, which will typically provide means, sample sizes, and standard errors. I am...
  5. G

    Fieller-Hinkley Ratio of Correlated Random Variables: Question On Applying Theory

    I am a senior in college writing a thesis analyzing and critiquing government income transfer programs, such as SNAP (food stamps). Here is my issue. I am using data collected from the consumer expenditure survey, which will typically provide means, sample sizes, and standard errors. I am...
  6. R

    How to create an unbiased fit to the data (Keyboard log data for each user)

    Hi all , So I have a very simple distribution of events (eg user keyboard log for five employees). Now if suppose I consider frequency of each key pressed for a single user, and for all users. And then suppose I want to see what distribution this data follows ( without any bias toward any...
  7. T

    Negative Binomial Distribution? NEED ADVICE AND HELP!!!!

    Assume City A has three parties, Party B, Party C, and Party D, with n1, n2, n2 citizens in them, respectively. Assume, for people in B, they will always support the motion by the government, while, for people in C, they will always be against the government. However, those in D will support the...
  8. P

    distribution of sum of dependent binomial variables

    I have N bernoulli dependent variables, X1, X2, ..., XN, and Xi ~ B(1, pi), pi is already konwn. And Y=X1+X2+...+XN, I need to get the distribution of Y. If Xi, Xj is independent, then I can use the simulation, generate X1,...,XN using the bernoulli distribution, and get the Y; repeat 10000...
  9. Y

    Question about Standard Normal Distribution (Finding probability)

    Suppose Z is a random variable having the standard normal distribution. 1)Find the probability that Z is between 0 and (1.08 + R/10) 2)P(–w < Z < w) = 0.8942 - R/50, Find the values of w My Answer: P(0<Z<1.08+R/10) =P(Z<(1.08-0)/1) =P(Z<1.08) =0.5+0.3599 =0.8599 is this correct?
  10. K

    Difference powerlaw, lognormal and streteched exponential (Weibull) function

    I am currently fitting above mentioned functions to my data and I can observe, that both lognormal and Weibull are better fits than powerlaw. In literature, it is often suggested, that it is hard to distinguish these functions, but I can in my data. I do not completely understand the...
  11. S

    Normal Distribution

    I cant figure out how to do this problem: I have 2 sets of means and 2 sets of SD 1sth graders scored a mean of 25 and a sd of 5 5th graders scored a mean of 30 and an sd of 10; assume the distributions are normal How do i figure out what percentage of the first graders scored better...
  12. S

    Help with the Beta Distribtuion

    Background: I'm currently trying to learn how to use Bayesian Analysis for split testing two sets of binomial data. (Web analytics, Multi-Armed Bandit approach, etc). The Beta distribution kept coming up in this research, so Im trying to understand and apply it better. So, the best...
  13. K

    What asymmetric distribution represents this data?

    Hello, I have this data: Bin particle_240 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 2 11 0 12 0 13 0 14 0 15 0 16 0 17 0 18 1 19 3 20 1 21 2 22 3 23 10 24 8 25 6 26 5 27 7 28 14 29 11 30 14 31 14 32 16 33 17 34 12 35 17 36 16 37 17 38 26 39 19 40 26...
  14. C

    Does vce(robust) correct not normally distributed errors (dependent variable)?

    Hello everyone, I have a question regarding the vce(robust) command in Stata. I have used this command for dealing with heteroskedasticity. I have also found that the residuals of the dependent variable are not normally distributed. I used pnorm, qnorm, kdensity and swilk commands for...
  15. B

    Software to Determine Data Distribution

    Does anyone know of any statistical program that takes a set of empirical data and determines what probability distribution it most closely matches? This would be ideal if a package existed in Python or R. Thanks for the help! -Ben
  16. J

    Distributions and means - confidence interval question

    Hi folks, :wave: I think I did my research but I would like to be sure before continuing. My task is to find the mean price of a given item in a given country and I need to know how accurate my sample mean is vs. the actual population mean. Here is what I have. (My proposed, probably...
  17. F

    Sampling Distributions help

    Hi, I'm teaching myself stats but have no idea on how to solve these, any help would be appreciated. When a pizza restaurant’s delivery process is operating effectively, pizzas are delivered in an average of 45 minutes with a standard deviation of 6 minutes. Suppose each night, 9 deliveries...
  18. A

    Need help with Uniform probability distribution

    Hey guys... I'm sort of confused about these two problems. If you guys can help me out that would be great. Problem: Suppose X is a random variable best describe by a uniform probability distribution with c=3 and d=5 . Find the following probabilities. a) p(x<4) b) p(x>2) Thanks,
  19. K

    I really need help on my homework!

    Theres 2 questions I'm really stuck on. One has three parts and is of course one of those "you can't do the next step until you get the first step" kind of thing.\ 1.A set of reading scores for fourth-grade children has a mean of 25 and a standard deviation of 5. A set of scores for...
  20. K

    Standard normal distribution

    Can someone please help me answer this Q with workings so I learn? Using a survey in winter 2009, it was estimated only 1% of households have solar panels to generate electricity. Consider a random sample of 20 houses. a) What is the probability that none of them have solar panels to...