Joint Definition and 297 Threads

we're going to start trusses soon (statics) and I want to know if I should pay attention to several screws on a joint...for instance, I attached a question and in the drawing I see sometimes 2 and sometimes 3 screws on a joint...is it relevant, or should I treat them as though they were one screw?

ATK, EADS Astrium To Develop Liberty Rocket. http://online.wsj.com/article/SB10001424052748704422204576130482887509152.html The team wants to build a low-cost commercial launcher (300 ft tall) to lift U.S. astronauts and scientific payloads into space. Looks similar to the proposed ARES...

What exactly is a "joint characteristic function"? I want the characteristic function of the joint distribution of two (non-independent) probability distributions. I'll state the problem below for clarity. So my two distributions are the normal distribution with mean 0 and variance n, and the...

True or false: "Every joint CDF has only one global maximum at F(x1*, ..., xn*) = 1? I know that the multivariate CDF is monotonically non-decreasing in each of its variables. But does that imply that it has only one global maximum? Is it possible to have two or more separate peaks where the...

Hello, I would gladly appreciate any and all help with this joint density problem a practice problem for an exam. Please excuse my lack of use of the proper symbols, I don't know how to express them online unfortunately : Joint Density of two random variables, U and V is: f(u,v)= 1/u...

Homework Statement X and Y have uniform joint density function: f(x,y)= d (constant) for 0<x<1 and 0<y<1-x 1. find d 2. find p(y<x) 3. find cov (x,y)The Attempt at a Solution 1. For this I first graphed x=1 and y=1 and created a square since x can go from 0 to a maximum of 1 and y also. I...

Homework Statement This is just a general question about understanding. What is the difference between a joint distribution functions vs. a joint density function. Homework Equations The Attempt at a Solution Are joint density functions basically the joint distributions of...

Homework Statement Suppose X and Y have joint density f(x,y)=2 for 0<y<x<1. Find P(X-Y>z) According to the textbook the answer should be (1-z)^{2}/2 Homework Equations The Attempt at a Solution \int \int 2dxdy for x=[0, z+y] and y=[0,1] =\int 2(z+y) dy =2z+1 since we...

I know assignment questions and such aren't meant to be placed in here, but there's no spot in the "homework section" that's meant for statistics. Move this to the appropriate section if necessary; I couldn't find it. Here I have an image of the questions we are meant to answer. The...

Homework Statement I have 2 variables that are both i.i.d. X1 and X2. i.i.d means they both have the same distribution and are independent of each other. My question is, how do i get the joint distribution: Fx1,x2(x1,x2) of these variables?? Homework Equations The Attempt at a...

Homework Statement X and Y are random variables with the joint density: fXY(x,y) = k*e^(-lambda * x) if 0 < y < x < infinity = 0, otherwise Find P(X + 2*Y <= 3) Homework Equations I found k = lambda^2 The Attempt at a Solution I'm not sure exactly how to solve this, but...

Homework Statement 1. Calculate Fxy(.25,.25) 2. Calculate Fx(.25) 3. Calculate Fy(.25) Homework Equations f(xy) = 2 (x+y) if 0\leq x \leq 1 and 0 \leq y \leq x The Attempt at a Solution 1. without showing all of the steps of my integration (because I apparently can't work...

Let the joint PDF of (X,Y) be of the form: f(x,y) = 1/8x(x-y), 0<=x<=2, |y|<=x f(x,y) = 0 elsewhere Find P(X+Y<=2). The answer that my teacher gave was P(X+Y<=2)=∫01dx ∫-xx 1/8x(x-y)dy + ∫12dx ∫-x2-x 1/8x(x-y)dy I do not understand how my teacher could separate the integral like...

Suppose X and Y are continuous random variables with the joint pdf f_{xy}(x,y) on the [0,1] \times [0,1] square. Is the probability P(X = Y) then equal to zero since probability here is a volume, and the set that satisfies P(X = Y) is a plane? Supposing it's not zero, when I tried to evaluate...

Hello everyone, I am trying to understand a paper and am stuck at one place. The statement says something as follows: Say we have a, b, c and d which are random variables generated by some model. This leads to the following joint probability model: p(a, b, c, d) =...

Homework Statement Basically, this is the problem. [PLAIN]http://img180.imageshack.us/img180/3598/physicsproblem.png It's related to some design research I'm doing regarding a centrifugal control valve. This is a type of valve that controls the fluid flow based on the centrifugal...

Ok I am not sure if I should put this question in the homework category of here but it’s a problem from schaums outline and I know the solution to it but I don’t understand the solution 100% so maybe someone can explain this to me. Let X and Y be defined by: \begin{array}{l} X = \cos \theta...

Homework Statement X and Y uniformly distributed on the disc: 1/pi, x^2+y^2 <=1 X=Rcos(theta), Y =Rsin(theta) 0<=R<=1, 0<=theta<=2pi Find the joint PDF of R,theta The Attempt at a Solution g(R,theta)=f(x,y)*abs(jacobian) The Jacobian is R The joint PDF is then simply R/pi = 1/pi (since...

Friday morning I was sitting at my desk when I felt this burning sensation in my left hand. Suddenly the middle joint of my index finger started swelling up and it was very painful. Then the middle joint turned purple and looked like it had been hit with a hammer. It's been two days now and...

Don't know there are anyone can help me out with this. This is just something I asking myself, not a homework I must say. Let's define X and Y are 2 standard normal random variables. And random variable Z=X+Y. For real number a, we know P(X>a), the probability of X is greater than the...

When solving for reactions in a 2D diagram as seen below, how does each type of joint affect the summation of forces in the x & y components? My problem asks to find the summation of forces in the x & y components, and has a smooth pin connection in the left of the beam and roller on the right...

Homework Statement The thermal conductivity of aluminum is twice that of brass. Two rods, one of aluminum and the other of brass, are joined together end to end in excellent thermal contact. They are of equal lengths and radii. The free end of the brass rod is maintained at 0°C while...

P(A|B)=\frac{P(B|A)P(A)}{P(B)} P(B|A)P(A)= \frac{(P(B)\cap (P(A)) P(A)}{P(A)}=P(B)\cap P(A)=P(A)\cap P(B) P(A|B)=\frac {(P(A)\cap P(B))\vee (P(B)\cap P(A))}{P(B)} 0\leq(P(A)\cap P(B))\leq P(A); P(A)\leq P(B) 0\leq(P(B)\cap P(A))\leq P(B); P(B)\leq P(A)

Homework Statement X,Y,Z random variables. Let Y and Z be two independent continuous random variables with common probability density function f(x) =2exp(-2x); x > 0 0; x < 0 (i) Specify the joint probability density function of (Y;Z). (ii) Fix x > 0. Let h(y; z) = 1...

Homework Statement Homework Equations If X and Y are statistically independent, then f(x,y) = g(x)h(y) where g(x) = \int f(x,y) dy h(y) = \int f(x,y) dx The Attempt at a Solution (a) g(x) = \int f(x,y) dy = \int_{y=0}^{1-x} 6x\, dy \Rightarrow g(x)=6x(1-x) and...

Problem: Suppose that the probability that a head appears when a coin is tossed is p and the probability that a tail occurs is q=1-p. Person A tosses the coin until the first head appears and stops. Person B does likewise. The results obtained by persons A and B are assumed to be independent...

Hello, I have a problem I need help with: Homework Statement There are 10 different types of coupons, each with prob 1/10 of being chosen. A total of N>=1 coupons are collected. Xi= 1 if type-i coupon is among the N coupons, i =1, ..., 10 0 otherwise Let S=X1+X2+X3 be the number of...

I have a region R = {(x,y): |x| + |y| <= 1} I have sketched the graph on the x-y plane and shaded in the region R (I got a diamond). How do I find the area of R and hence find the joint density function f(x,y) and how do I specify the region for which f(x,y) is non-zero.

Obtain marginal probability mass function (pmf) given joint pmf Not really a homework question, but it does have a homeworky flavor, doesn't it... Homework Statement Given a join probability mass function of two variables, is it always possible to obtain the marginals? E.g., if I have a...

Homework Statement f\left(x,y\right)=\left\{\begin{array}{cc}\frac{1}{y} ,&\mbox{ if } 0 \leq x \leq y, 0 \leq y \leq 1 \\ 0,&mbox{ otherwise } \end{array}\right. Find the marginal distributions (pdf and cdf) of X and Y Find Pr(X+Y>0.5) Homework Equations N/AThe Attempt at a Solution...

Homework Statement X1 and X2 represent the values of two honest dice throws (independent of each other). Find the joint probability function of U and V when: a) U = min{X1,X2}, V = X1 + X2 The Attempt at a Solution This is what I thought: P(U = u,V = v) = P(\min \left\{...

Homework Statement Given: f(x,y) = x + y, for 0<x<1 and 0<y<1 f(x,y) = 0, otherwise Derive the joint distribution function of X and Y. Homework Equations N.A. The Attempt at a Solution Using the definition, I obtained part of the joint distribution F(x,y) = (1/2)(xy)(x+y)...

Please explain in detail about toggle joint, especially about its mechanical advantage.

Homework Statement Two players, A and B, try to see who has the fastest reflects. They test this by using a button, and whoever presses the button first when a light goes on, wins. Let's assume both A and B are random variables ~U(0,1) and are independent (time in seconds). May W = "winner's...

Homework Statement John and George are set to meet each other at 12 o'clock. John's time of arrival, J, is distributed uniformly between 12:00 and 12:15. John will wait for George for 15 minutes. If he doesn't show up, he leaves. George's time of arrival, G, is also uniformly distributed...

Dear all I have the following problem. Given a set of correlated binary variables, can I determine the joint probability from the correlation function? {Xi} is a set of binary variables Pr(Xi=1) = p and Pr(Xi=0) = q for all i Corr(Xi Xj) = cij cij is symmetric Now how can I determine the...

if the joint p.d.f of x,y is given by f(x,y)= a |x-y| ,0<=x,y<=1 f(x,y)= 0 , o.w find i)a ii)p(y>x) iii)p(x=y)

Homework Statement Stuck on this for quite some time. http://img685.imageshack.us/img685/1387/22580211.png Homework Equations The Attempt at a Solution I've drawn the component parts in question. Don't know where to even begin to find this solution (dont have my scanner here too). I am...

I'm a science freshman (U0) at McGill and I can't seem to find the answer to this question on any website. I've sent it by email to my advisor, but have not got a response back yet. My question to anyone that goes or has gone to McGill is: What exactly are the requirements for entry into the...

Are any two (or n) random variables always jointly distributed in some sense? When will two RV's be non jointly distributed? Saurav

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 X1 and X2 are independent~u(0,1) Y1=X1+X2 Y2=X1-X2 Find the density function of Y1 Homework Equations X1=(Y1+Y2)/2 X2=(Y1-Y2)/2 0\leqY1\leq2 -1\leqY2\leq1 0\leqY1+Y2\leq2 0\leqY1-Y2\leq2 -y1\leqy2\leq2-y1 -1\leqy2\leqy1 The Attempt at a...

Homework Statement Let X and Y be independent uniform (0,1) random variables. a. find th ejoint density of U=X, V=X+Y. b. compute the density funciton of V. Homework Equations The Attempt at a Solution Part a. is not a problem. I don't understand how the bounds for part b...

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...

Evening everyone, i have been referring to Shigleys "Mechanical engineering design" (pages 349 to 351) regarding a welded joint I am looking at. wanted to compare my manual calcs to sum FEA. My joint is a circular shaft which is fillet welded to a base plate. A load is applied to the end...

hello i have given this problem to find pdf of function z.i have solved most of it and stuck at the end. i have attached problem and my solution so far as pdf here. what i want to know what are the integral limits for finding f(z) using marginal density (see the end the end of attached...

Homework Statement Homework Equations Well i know the double integral formula for the joint pdf The Attempt at a Solution So firstly we're told to find the joint pdf of X and Y. I'm not sure where to begin. So how do we find the function that we take the double integral over? I'm...

Homework Statement If and where X,Y are independent and identically distributed (i.i.d) random variables uniformly distributed over the interval (0,2). Z=X-Y W=X+Y (a) Find the joint pdf of Z and W . (b) Show that even though the random variables Z,W are uncorrelated they are not...

Homework Statement A dancer stands on his left leg (knee extended), torso and arms forwards outstretched horizontally. The right leg (knee extended) is backwards outstretched horizontally. The dancer weighs 55 kg. The length of the thigh is 35 cm, the shank 45 cm. Draw the free body diagram...

Homework Statement Let X and Y be two random variables, with joint distribution given by the following table: a b 1 2 3 4 -------------------------------------- 1 16/136 3/136 2/136 13/136 2 5/136 10/136 11/136 8/136 3...