Pdf Definition and 346 Threads

Homework Statement For a given cdf: Fy(y) = 0 for y less than 0 = y^2 for the range 0 to 1 = 1 for all values greater than or equal to 1 the problem asks to find P(1/2 < Y < 3/4) first using the cdf and then using the pdf...

Homework Statement I understand that PDF is a derivative of CDF and hence CDF is the integral of PDF. But I don't understand the difference between PDF and simply probability? What exactly is the differece? What extra things does PDF tell us which simple probability does not? Homework...

Hey all i struggling to understand, these concepts. would some explain to me the relationship and differences the distribution of a random variable and a probabiltiy distribution. wikipedia says this about probability distribution "The probability distribution describes the range of possible...

Hi everyone, I have a simple question (assuming since it was only worth 5% of total marks in the exam) about the PDF of a random variable. Given that PDF of random signal equals p(X) = \Lambda(X), where \Lambda is the triangle function, what would be the PDF of the random signal Y, Y = -3X...

Hi guys, I was reading about monte carlo analysis in the introduction from a textbook, and they gave an example of a voltage divider. They assumed resistor values had an equal probability of having values between the two tolerances. I know this is a simplistic assumption and I was wondering...

Determination of a Joint pdf Hi all! Someone can help me with this problem? The duration of a certain type of bulbs has a exponential distribution with known parameter \lambda . Consider a set of n bulbs. Which is the joint pdf of the durations t_{i} of the n bulbs?

Homework Statement problems 4 and 7 from this pdf http://www.daisleyphysics.com/y2p/worksheets/em4ws5.pdf Homework Equations The Attempt at a Solution A friend of mine is bad with computers and she asked me to help find the answers.

Homework Statement Let X1 X2 X3 be independent and identically distributed random variables with common pdf f(x) = e^-x 0<x<infinity, zero elsewhere. Evaluate P(X1 < X2|X1 < 2X2) and P(X1 < X2 < X3|X3 < 1). The Attempt at a Solution Would appreciate any hints as to where to start...

Homework Statement Let X1 X2 X3 and X4 be four independent random variables, each with pdf f(x) = 3(1-x)2, 0<x<1, zero elsewhere. If Y is the minimum of these four variables, find the cdf and pdf of Y. The Attempt at a Solution P(Y<or= y) = 1 - P(Y>y) = 1 - P(X1>y, X2>y, X3>y...

Homework Statement Suppose X1 and X2 are two independent gamma random variables, and X1~Gamma(a1, 1) and X2~(a2, 1). a) Find the joint pdf of Y1 = X1 + X2, and Y2 = X1/(X1 + X2). b) Show that Y1 and Y2 are independent. c) Find the marginal distributions of Y1 and Y2. The Attempt...

Homework Statement Normalise \Psi(x,t) = Ae^{-\lambda |x|}e^{-i \omega t} Homework Equations (i.e. it must satisfy \int_{-\infty}^{\infty} |\Psi (x,t)|^2 dx=1) The Attempt at a Solution This is my first attempt at normalisation and I don't know how valid my reasoning is, can...

I have just been learning probability density function (pdf) and there is something I need to ask. I understand the idea that for any value v, the pdf (f(v)) gives the probability that a value picked from a data set is less than v. It seems ok to find mean,variance, skewness etc. when f(v) is...

Homework Statement Let X be uniformly distributed over [0, 1] and Y be exponentially distributed with λ=1. Assuming X and Y are independent, give the PDF of Z=X/Y. Homework Equations The Attempt at a Solution I know the individual PDFs of X and Y. I was trying to use a geometric...

A Geiger counter records the times at which radioactive particles are detected. However, if two particles occur within a short time θ of each other, the second one is not detected. Then, the probability density function of X, the time between successive recorded detections, is f(x) = k...

cdf to pdf and vise versa hi i'm looking for help when going from a cdf function: F(x) = { 1- e^-αx^β x ≥ 0, α>0, β>0 { 0 x < 0 to getting the corresponding pdf also i am looking to do the opposite(pdf to cdf) for: f(x) = { (1 + α)/2 for -1 ≤ x ≤ 1, -1 ≤ α ≤ 1 { 0 otherwise i'm...

hi i'm looking for help when going from a cdf function: F(x) = { 1- e^-αx^β x ≥ 0, α>0, β>0 { 0 x < 0 to getting the corresponding pdf also i am looking to do the opposite(pdf to cdf) for: f(x) = { (1 + α)/2 for -1 ≤ x ≤ 1, -1 ≤ α ≤ 1...

Homework Statement In a square town that is 1.5 miles by 1.5 miles, the places of residence are uniformly distributed (2000 per square mile) over the whole town. Compute the joint probability density function for the spatial distribution of places of residence (fX, Y). Homework Equations...

Hi guys! Homework Statement Do you know how to get the cdf and pdf of the absolute difference of two iid standard uniform X1 and X2 : X = |X1 − X2| ? Homework Equations Come across...

Hello, Suppose that we have the following set of independent and identically distributed RVs: \gamma_1,\,\gamma_2,\,\ldots,\,\gamma_M. Arranging them in descending order as: \gamma_{1:M}\ge\gamma_{2:M}\ge\cdots\ge\gamma_{M:M}. Now suppose we select the largest m\leq M order statistics. What...

How can I create a PDF file w/out buying anything? Why does adobe try to swindle you into buying something? It's cake on my Mac, but on my PC not so much. So what do you guys use? Thanks, Casey

Is there any free way to split PDF pages down the middle? I have a scanned PDF book with 2 pages on each page. Is there any way I could split the whole doc down the middle so there is 1 book page per page.

Hi, all, I am having a problem in calculating a randomly truncated pdf. Let x be a random variable, it's pdf f(x) is known. Let t1 and t2 be anther two random variables, their pdf f(t1) and f(t2) are known as well. Now, how do I compute the pdf f(x|t1<x<t2)? Thks a lot.

I have a pdf file and I need to save to disk only part of it, not the whole document. Does anyone know how to do that? I have the LaTeX file and I can of course LaTeX only part of the file but the problem is that the references in the part that I LaTeX are then not working since they refer...

Hi,all, I have a problem of computing pdf of some random variables. Assuming x1, x2... xN are some random variables. Now, I know the pdf of x1, which is f(x1). For the pdf of x2, it is given as a function of x1, in this case, how do I compute pdf of x2? Or, rather, how do I generate samples...

Hello, Suppose that: Z=X_1+X_2+X_1X_2 where X_i for i=1 and 2 are independent and identically distribuited exponential RVs. can we find the PDF of Z? Regards

I am confused as hell. If you look at exponential distribution at wikipedia or elsewhere, you can see that the pdf can attain values larger than 1. How is it possible? This basically implies that probability density of some value is larger than 1? :mad:

Hello, Is the relation between the PDF and CDF of order statistics is as any PDF and CDF. i.e.: F_X(x)=\int_{-\infty}^{x}f_X(t)\,dt Regards

Hello, I have this equation: \int_{-\infty}^{\gamma}f_X(x)\,dx+\int_{\gamma}^{\infty}F_Y(x-\gamma)\,f_X(x)\,dx where f_X(x) and F_Y(y) are the PDF and CDF of the randome variables X and Y, respectively. Now the question is: can I write the above equation in the form...

Homework Statement Hi Guys, I have been given the following The random variable X has a gamma (\alpha,\beta) distribution; ie X has pdf f_{X}(x)=\frac{x^{\alpha-1}e^{\frac{-x }{\beta}}} {\Gamma (\alpha)\beta^{\alpha}}\text{for }x \geq 0 (a) Determine the pdf of...

Is the expected value E[x]or E[y] of a bivariate pdf fXY(xy) \int x f(x,y)dx or E[y] \int y f(x,y)dy ? example if f(x,y) = x+y E[X] = \int x *(x+y)dx regards Brendan

Dear all, what are the differences between Caroll´s GR published book and the PDF text? Thanks, Goldbeetle

I'm having a lot of trouble figuring out the difference between a probability density function and a cumulative distribution function. Is the CDF just the integral of the PDF? Thanks in advance.

Joint PDF --> Marginal Pdf's Homework Statement Suppose that the random vector (X, Y ) has the probability density function (pdf) fX,Y (x, y) = k(x − y), if 0 < y < x < 1 0, otherwise. 1. Find the value of k, so that fX,Y (x, y) is a genuine pdf. 2. Find the marginal...

I'm not sure where to have put this question I hope it is in the right place. I have big problem with LaTeX.. I have been writing a document for a while and recently when I click the build and view button it shows this error [DocOpen(%bm.pdf")][FileOPen(%bm.pdf)] Cannot execute the...

I'm not sure where to have put this question I hope it is in the right place. I have big problem with LaTeX.. I have been writing a document for a while and recently when I click the build and view button it shows this error [DocOpen(%bm.pdf")][FileOPen(%bm.pdf)] Cannot execute the...

Hi. The question is: Given X, Y and Z are all continuous, independant random variables uniformly distributed on (0,1), prove that (XY)^Z is also uniformly distributed on (0,1). I worked out the pdf of XY=W. I think it's -ln(w). I have no idea at all how to show that W^Z is U(0,1). What...

I have been asked to determine the pdf given a DF. F(x) = 0 for x<0 F(x) = x^2/x for x 0<= x < 1 F(X) = x/2 for 1<=x<2 F(x) = 1 for x>= 2 Is the pdf the derivative of the df So if you wanted the probability of x between 0 and 1 The pdf would just be x ? regards Brendan

Homework Statement Hi. I need to insert this equation in a pdf file such that it doesn't cut off. How can I make it appear without cutting off? Homework Equations \noindent\(\sqrt{\frac{1}{2} e^{\frac{1}{2} \text{$\kappa $u} (-4 u+4 \text{u0}+\text{$\kappa $u})} \sqrt{\pi }...

Homework Statement I have a probability distribution function (PDF) going fromi 0 to a on the y-axis and 0 to 30 on the x-axis. The function describing the PDF is the quadratic equation f(x) = a+bx+cx^2 I have to find a, b, and c. Homework Equations The Attempt at a Solution...

A question which I amnot able to do...please help: Find the PDF of Y if X is a Gaussian PDF: fx(x) = (1e-x^2/2)/(2pi)^1/2 ; -infnity<x<+infinity Express your answer in terms of CDF of X gven by Fi(x) = Integral -infnty to + infnity((1e-x^2/2)/(2pi)^1/2) b) Sketch both the PDF, fY(y)...

I am looking for an application to not only view pdf's but also type side notes and highlight sections. This application must be compatible with my platform: Linux - Ubuntu-8.10. Thanks

Does anybody know what the pdf of a sine wave cycle is? Or perhaps how to derive it? The problem can be done numerically, but surely there is an analytic expression for this function? There is a numerical solution available at...

Cambridge press says available as of around 1 March, so in a couple of months. Samples are available of page proofs as they will, I gather, appear in the book. Here's the 3-page table of contents http://assets.cambridge.org/97805218/60451/toc/9780521860451_toc.pdf Here's an 11-page exerpt...

Hi all, I am new here. I have a problem about statistics: now I have two variable a & b, both of them are uniformly distributed in [-1 1], I want to find the pdf of the function f=|a-b|/|a+b|. Any hint is welcome, thanks a lot xiaoli

Hey all, My bibliography is not showing up in the PDF output, and I'm not sure why.. The bib file is in the same directory as the the main tex file. I am using the command: \documentclass[a4paper,twoside,11pt]{book} \usepackage{calc} \usepackage{setspace} \usepackage{graphicx}...

I'm trying to find some software (preferably free) which allows editing of pdf files in Windows XP. I don't need anything too fancy, just the ability to add/remove/reorder/resize pages, and to add and remove bookmarks. Anyone have any suggestions?

Homework Statement The exam grades in a certain class have a Gaussian PDF with mean m and standard deviation \sigma. Find the constants a and b so that the random variable y=aX+b has a Gaussian PDF with mead m' and standard deviation \sigma'. Homework Equations The Attempt at a...

Que. 1 Consider a Gaussian PDF with µ = 20, σ = 30, a = 50 and b =80. Determine i)Probability that P(x>b) ii)P(x ≤ b) iii)P(x ≤ - b) iv)P(a ≤ x ≤ b) Que. 2 In a certain manufacturing process only shafts whose diameters are less than 1.5 inches can be used. Given the shaft diameters are...

Homework Statement A function f( x ) had the following form : f ( x) = kx^-(k+1) where 1 < x < infinity a) for what values of k is f a pdf ? Homework Equations See attachments (the theorem is included) The Attempt at a Solution started out by using the first equation in the...

Question is what is the mode when all data are unique? have a set wherein the actual question is what is the inference about the PDF for the data? Median > mean but no mode...i was under the impression that PDF is only for a continuous measurements...when data set is unique...in which case it...