1. I

    Domain of pdf from cdf

    Hello, probably obvious question, but what I would like clarified is, is the the domain of the cdf always the domain of the pdf once you for instance take the derivative of the cdf to find the pdf, the pdf will have the same domain right? Also related question, but if you find a function for a...
  2. M

    Conditional p.d.f. of a continuous bivariate distribution

    Consider the random variable X and Y with joint probability density function as: f(x,y) = 24xy for 0<x<1, 0<y<1, 0<x+y<1 Find the conditional p.d.f. of X given Y = 0.5 Here's what I've got: f_{Y}(y)=\int_{-x}^{1-x}24xydx=-24y^2+12y and then...
  3. M

    pdf for continuous random variable

    Hello again everyone, I'm having some trouble understanding an example for a probability density function of a cont. RV. The part I'm not getting is the integrals. I need an elaboration on what is going on with the calculations so I can see what is happening. I assume that it has something to...
  4. T

    PDF for incomplete function

    Suppose pdf of random variable Z is f(z) = ce-2z for z>0 Find C Find CDF Find Median I only got as far as trying to set up an exponential distribution with Beta = 1 so that the denominator of c and the exponent were 1. That would leave C to be any real number...
  5. E

    PDF / ML from a correlated sequence

    I have a stream that contains two consecutive identical sequences, each of length N. These sequences have a ideal autocorrelation property. All other samples outside of [1,..,2*N] are statistically independent. Background is that I want to create a likelihood method. So I want to have the...
  6. H

    Finding a joint pdf

    if the joint probability density of X and Y is given by f(x,y)=1y for 0<x<y,0<y<1 0 else where find the probability that the sum of values X and Y will exceed 1/2. So this would be x+y>1/2 But I am not sure how to set up an integral to solve this problem.
  7. C

    Given a pdf, find...

    One of the question on my stats assignment comes as follows: The n candidates for a job have been ranked n = 1,2,3,...,n. Let X = the rank of a randomly selected candidate, so that X has the following properties: p(x) = 1/n for x=1,2,3,...,n p(x) = 0 otherwise a) Find E(X) b) Find Var(X)...
  8. C

    converting LaTex pdf to powerpoint slides

    hi fellas,I want a little help from you regarding powerpoint presentation. I made a pdf document from LaTex, but my supervisor wants it to be of .ppt format. If I use the online converters , my fonts are messed up. is there a way I can work directly in .ppt format in LaTex. I used...
  9. M

    pdf of Beta distribution > 1

    I am confused about the values of the probability density function exceeding sometimes the value one on the Beta distribution. Could you clarify me this point, please ? Thanks in advance.
  10. R

    Solving Functional Equation for PDF

    Hello to everyone, how to solve following functional equation having that "f" is a probability density function of variable "x"? f(x)/f(-x)=exp(b*(x-G)) Regards, Rafael
  11. A

    Derivation of PDF forumula

    \frac{P(x_{0} > X > x_{0} + \epsilon)}{\epsilon} \rightarrow f(x_{0}) as \epsilon \rightarrow 0 I'm finding this a bit confusing. I understand that it's supposed to represent that as \epsilon aproaches 0 the probability will be f(x_{0}), I just don't quite understand hwo it's derived...
  12. A

    Statistics - PDF, E(U), Probability

    Gasoline is to be stocked in a bulk tank once at the beginning of each week and then sold the individual customers. Let X denote the proportion of the capacity of the bulk tank that is stocked at the start of the week. Let Y denote the proportion of the capacity of the bulk tank that is sold...
  13. M

    Joint pdf

    Will somebody please help me in this problem. A point is chosen at random from the interior of a circle whose equation is x^2 + y^2 ≤ 4. Let the random variables X and Y denote the x- and y-coordinates of the sampled point. Find fX,Y (x, y). Thank you.
  14. A

    Linear transformation of pdf

    Can't understand this. The chain rule is used in third line but I can't understand that if Fx is f(x) then what is g(x)? I can't see any other function wrapping around Fx but then Fx just disapereas and we are let with just ((y-b)/a).
  15. A

    Theory behind Normal/Gaussian distribution pdf

    Hi all Many books mention about the pdf of the normal distribution, but where this pdf comes from? I would like to know the theory behind the pdf. Can someone point me to the right direction. Thank you in advance.
  16. M

    Fitting a Gaussian to high dimensional data with a discrete pdf defined over them

    Hi, I wonder if anyone can give me a handle on this problem. I have sampled 100,000 point from an isometric gaussian in 98 dimensional space (each point translates into a particular face in a "face space" model). I have then defined a uniform distribution over the 100, 000 points. so far so...
  17. L

    P(k|n,s) , what type of probability is this?

    I have to do a seminar and it has some maths in it, which i can't grasp. I know about probability of one variable, two variables and prob of one variable given the other variable...
  18. S

    Sample mean PDF

    I read a proof which showed that if X follows a normal distribution with mean \mu and variance \sigma^2 then the sample mean also follows a normal distribution with mean \mu and variance \frac{\sigma^2}{n}, is this true in the general case so that if a random variable Y has a probability density...
  19. S

    Turning LaTeX into PDF

    After using these forums for months I learnt how to write in LaTeX but not my friend showed me how he had written his Latex in notepad and turned it into a PDF which I thought was quite cool. I am now writing some mathematical documents over my holiday and I'd also like to know how to convert it...
  20. T

    Open university text books in PDF format

    Is it ok to ask on here about sourcing PDF copies of textbooks? I'm living in Thailand and my books are back in the UK and I was wanting to brush up on my skills to take some more courses. I've completed MU123, MST121, and a part of MS221. I'd love to have copies of the textbooks to look over...