Marginal Definition and 100 Threads

Suppose I have the marginal probability density functions of two random variables A and B, P(A), and P(B). Suppose I modeled P(A) and P(B) using a mixture model from some dataset D and obtained a closed form pdf for each. I am interested in finding their joint density function P(A and B) and...

Consider a set of n numbers, and let their arithmetic mean be X. Suppose a new number Y, is added to the set. Prove that the mean of the new set, with (n+1) members, is between X and Y. I've been trying to prove this the past few minutes, but I think I'm at a dead end. It's a problem that...

I had questions on 2 Problems in the Text: 1. The total cost C of producing x units of some item is a function of x. Economists use the term marginal cost for the rate of change of C with respect to x. Suppose that: C = 5x^2 + 15x + 200 What is the marginal cost when x = 15? Would this...

Hi.. Until very recently, I have what can be called a marginal interest in computers and even more so in math (mostly because any math I can do is limited to AS Level and despite being able to deal with abstractions in other disciplines, I seem not to have caught on the math front..I was also...

Hi, This is my first post in one of these forum; I hope someone can help me with this --thanks in advance for reading! I'm trying to find the joint probability distribution of two non-independent variables given only their marginal distributions. In fact, I'm interested in the joint...

Homework Statement The probability density function of the random variables X and Y are given by: f_1(x)= \begin{cases} 2 & -\frac{1}{4}\le x\le \frac{1}{4} \\ 0 & \text{elsewhere} \end{cases} and f_2(y) \begin{cases} \frac{1}{2} & 0\le y \le 2 \\ 0 & \text{elsewhere} \end{cases}...

given the marginal cost is equal to: 1/2*Q and i asked to Draw the manufacturer Supply graph. in the picture you can see my tried. Hope you can help. thanks.

Homework Statement suppose that the dollar cost of producing x washing machines is c(x)= 2000 + 100x-0.1x6^2 a) find the average cost of producing 100 washing machines. b) find the marginal cost when 100 washing machines are produced. Homework Equations c(x)= 2000 + 100x-0.1x6^2: the...

Homework Statement An electronics manufacturing company has determined that the cost of producing x units of its newest personal stereo is given by C = 4000 + 9.55x, and the monthly demand equation is given by px=20,000 - x/500. Find the marginal profit for a production level of 3000...

Hi, I am trying to find out what would be the significance of the result of multiplication of two marginal densities that originate from the integration of the a joint density function that connects them. To be more specific let's say we have a joint density function of two random variables...

Hi, If I have a joint probability mass function p_{X,Y}(x,y), can we get the marginal probability mass functions p_X(x) and p_Y(y), without any knowledge of the conditional probability function of either of them, and the probability of each event? I mean, I know that...

Hey guys, So I'm having trouble telling what the integration bounds should be when calculation the marginal PDF of two random variables. So the joint PDF fX1,X2(x1,x2) is a constant C = 1 in the regions x1 and x2. The regions are bound by 0<=x1<=1 and 0<=x2<=2(1-x1). If the marginal PDFs are...

Homework Statement Y1 and Y2 have a joint probability density function given by: f(y1,y2) = {8y1y22, 0<=y1<=1, 0<=y2<=1, y12<=y2 0, Elsewhere Homework Equations f1(y1) =ʃ f(y1,y2) dy2 f2(y2) =ʃ f(y1,y2) dy1 For E(Y) (later, discussed in part 3): E(Y1) = ʃ y1f(y1,y2) dy1 E(Y2) = ʃ...

Oops, I accidentally edited over this post =( Thankfully it's quoted in the next one.

If you are trying to pray towards Mecca for example (a small point on Earth's, assume spherical, surface) and you are standing on the exact other side your angle doesn't matter since every angle you face at will Cross mecca. Now my question is how do you go about calculating the effect of a 1...

Of course, as with everything else, I've felt that studying for a test often yields diminishing marginal utility. I sometimes get really frustrated when I talk to students who are obsessed with trying to get 4.0s (and who aren't happy with grades in the 3.6-3.7 range, even though these grades...

Homework Statement A nursery has determined that the demand in June for potted plants is p= 2.00 - (x/30000). The cost of growing x plants is C = 2000 + .20x, 0 \leq x \leq 100000 Find the marginal profit function. Homework Equations N/A The Attempt at a Solution I don't know where...

Statistics Help--Joint pmf and marginal pmfs Homework Statement Let X1 and X2 be iid discrete uniform random variables with support on the integers {1,2,3,...,n}. Find the joint pmf of Y=max(X1,X2) and W=min(X1, X2). Find the marginal pmf's of W and Y Homework Equations The...

Given: P(X=x, Y=y)=\frac{a^ye^{-2a}}{x!(y-x)!} where x=0,1,2,...y and y=0,1,2...\infty, and a>0 Find P(X=x) and P(Y=y) An example is provided in a book on books.google.com Page 96...

I have a question I need to answer. f\left(x,y\right)= 6x^2y such that 0<x<y and x+y<2 where f\left(x,y\right) is a probability density function for two random variables: X,\;Y I need to find marginal density distribution for the random variables X and Y It appears to be a straight forward...

What is marginal stable airplane?

Homework Statement Calculate the marginal density of fx (x). Fx,y (x,y) = double integral of 4x.e^(x+y) when 0<x<y, 0 otherwise. Homework Equations The Attempt at a Solution i set up the equation as fx (x) = integral from x up to infinity of 4x.e^(x+y) dy i get 4x...

hi all, the situation is this: i have a conditional PDF f_{X|(D,S)}(x|d,s) and the unconditional PDFs D and S, f_{D}, f_{S}. Now, I can marginalize the joint PDF f_{X,D,S}=f_{X|(D,S)}f_{D}f_{S} by integrating over d and s over their respective supports. What I'm really interested in is a...

Much recent economic efficiencies have come from economies of scale and specialization of labour. http://en.wikipedia.org/wiki/Thomas_Robert_Malthus but at what point is there diminishing marginal return. The more people we have the more tasks can be broken down into smaller and smaller...

Homework Statement The integral from 0 to infinity of xe^[-x(1+y)]dy Homework Equations The Attempt at a Solution I can't figure out why the answer would be zero to a pdf. Also, for the indefinite integral the calculator produces the answer xy*e^(-x-xy). I cant' figure out...

This question is not homework(I'm not even in school). Also, I know how to get the answers but have a question regarding the reasonableness of an answer. This is taken from a calculus book in the chapter introducing the derivative. Problem: It costs C(x)=50+\frac{1}{4}x-\frac{1}{30}x^{2}...

STAT134/150: Marginal distr. of a random var. w/ random var. param., given distrs Hello, I am a little shaky on my probability, so bear with me if this is a dumb question... Anyway, the distributions of the two random variables are given: X : Poisson (\lambda) \lambda : Exp. (\theta)...

I am a little shaky on my probability, so bear with me if this is a dumb question... Anyway, these two random variables are given: X : Poisson (\lambda) \lambda : Exponential (\theta) And I simply need the marginal distribution of X and the conditional density for \lambda given a value for X...

Homework Statement Calculate the marginal probability distribution function of X given joint pdf f(x,y) = 15x^2 y for 0 <= x <= y <= 1 f(x,y) = 0 otherwise Homework Equationsf_x (x) = integral of f(x,y) dy The Attempt at a Solution I've got no idea what the bounds are for this integral...

If I have a set of Probability distributions on a product space with marginal constraints, is there any way to (how to) express the same as a linear family of PD's ( i.e. all P s.t. E_P[ f_i] =a_i for some f_i, a_i )

Homework Statement A company's Marginal profit is P'(x) = -0.0105x^2 + 0.14x + 25 where x represents hundreds of items and profit is thousands of dollars a) Estimate the change in profit it the production is raised from 80 to 81 hundred units. Should the manager increase production? b)How...

1. Utility function of an individual: U=U(x_1,x_2)=(x_1 +2 )^2 (x_2=3)^3 Where x_1 and x_2 are the quantities of two commodities consumed. 2. Question: FInd the marginal-utility function of each of the commodities and the value of the marginal utility of the first commodity when 3 units of...

Hi, I have a regular OLS regression that includes a variable both by itself and squared (i.e. y=b0+b1*x+b2*x^2). I am interested in the marginal effect of the variable at the mean. I know how to get the point estimate, but does anyone know how to get standard errors for the marginal effect...

Homework Statement Mondo Inc. estimates that it can sell 3400 of its premium espresso machine, the Caffeinator, at a price of $900 each, but it will lose 100 sales for each $50 increase in price of the machine. Let p be the price and q be the number of machines sold. (a) Write q as a linear...

Hi I am trying to find a way to create a marginal distribution plot in matlab. I have lots of X-Y values on a scatter plot and need to find the approximate distribution. I have the Statistics Toolbox which is probably needed. I used POLYTOOL which gives me a mean and standard deviation...

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...

Marginal Probability function?Anyone I have this question which I cannot seem to solve: The joint probability mass function p(x, y) of two discrete random variables X and Y is given by. p(x,y) = ([5^x][7^y][e^-5])/x!(y-x)! x and y are non-negative integers and x <= y (i) Find the marginal...

I have this question which I cannot seem to solve: The joint probability mass function p(x, y) of two discrete random variables X and Y is given by. p(x,y) = ([5^x][7^y][e^-5])/x!(y-x)! x and y are non-negative integers and x <= y (i) Find the marginal probability mass functions of X and Y.

Finding marginal Probability Functions ? Anyone I have this question which I cannot seem to solve: The joint probability mass function p(x, y) of two discrete random variables X and Y is given by. p(x,y) = ([5^x][7^y][e^-5])/x!(y-x)! x and y are non-negative integers and x <= y (i) Find...

I understood the concept and definition of marginal rate of substitution , and also MRS = -(dy/dx) , but why is dy/dx never positive ?

The difference btwn marginal distribution and conditional distribution ? So I have a table that "apparently" shows how a company's employees commute to work. TRANSPORTATION JOB CLASS CAR BUS TRAIN TOTAL...

Find the marginal probability functions of a) X and b) Y f(x,y)=cxy for x=1,2,3 y=1,2,3 (discrete data) The first thing I did was solve for c, which turned out to be 1/36. The book confirmed this. Next I setup a table, for x=1 the total would be 6c, x=2 12c, x=3 18c. So for the...

I'm not sure I understnad what is a marginal distribution, but i need to show that if F1,F2 are one dimensional cummulative distribution functions then I(x,y)=F1(x)F2(y) has F1 and F2 as its marginal distributions. well if I(x,y)=P(X<=x,Y<=y) and if X and Y are independent, then it equals...

Homework Statement Suppose the total cost of producing x units of a certain commodity is C(x)= (1/4*x^4) + (-37/3*x^3) + (280/2*x^2) + (1200x) + (100) Determine the largest and the smallest values of the MARGINAL cost C'(x) for 0<x<18 The largest value of the marginal cost is...

Hey guys, Doin revision for my maths exam and i came across this question from a past exam: Homework Statement Find fx(x,y) of f(x,y) = \frac{(1+4xy)}{2} for 0 \leq x, y \leq 1 and zero otherwiseHomework Equations Now this should equal \int \frac{(1+4xy)}{2} dy over all y but that leads to...

really need help! I really have to figure out the answers to these questions and i don't know where to start. I don't know how to draw the marginal benefit and marginal cost curves for this question. a.Sketch a marginal benefit and marginal cost diagram, with “billions of units of security...

I just started learning microeconomics and i am already confused. I was reading production possibility frontiers and how marginal cost and marginal benefit are related. I know that marginal cost is the slope of the PPF, and by doing this i get graph a marginal cost curve, but how do i calculate...

i know this is not exactly where you post help questions but i really need it. heres my questions. I just started learning microeconomics and i am already confused. I was reading production possibility frontiers and how marginal cost and marginal benefit are related. I know that marginal...

We're in the derivatives chapter, so we assume finding the answer to this requires the use of a derivative, but we are completely lost. A bus will hold 60 people. The fare charged (p dollars) is related to the number x of people who use the bus by the formula p=[3-(x/40)]^2. (a) Write a...

This is a problem from a section on marginal analysis in a calculus textbook I have been studying. I can't ask the instructor, since I don't have one, I'm just studying this for my benefit. The problem is as follows: A firm's costs are given by: C(q) = Kq^{1/a} + F Where a is a...