Friday

April 25, 2014

April 25, 2014

Total # Posts: 551

**Probability**

For any given flight, an airline tries to sell as many tickets as possible. Suppose that on average, 10% of ticket holders fail to show up, all independent of one another. Knowing this, an airline will sell more tickets than there are seats available (i.e., overbook the flight...

**Probability**

Let X be a continuous random variable. We know that it takes values between 0 and 3, but we do not know its distribution or its mean and variance. We are interested in estimating the mean of X, which we denote by h. We will use 1.5 as a conservative value (upper bound) for the...

**Probability**

For each of the following sequences, determine the value to which it converges in probability. (a) Let X1,X2,… be independent continuous random variables, each uniformly distributed between −1 and 1. Let Ui=X1+X2+⋯+Xii,i=1,2,…. What value does the sequenc...

**Probability**

Let Θ be an unknown random variable that we wish to estimate. It has a prior distribution with mean 1 and variance 2. Let W be a noise term, another unknown random variable with mean 3 and variance 5. Assume that Θ and W are independent. We have two different instrum...

**Probability**

Consider a fire alarm that senses the environment constantly to figure out if there is smoke in the air and hence to conclude whether there is a fire or not. Consider a simple model for this phenomenon. Let Θ be the unknown true state of the environment: Θ=1 means th...

**Probability**

Manhole explosions (usually caused by gas leaks and sparks) are on the rise in your city. On any given day, the manhole cover near your house explodes with some unknown probability, which is the same across all days. We model this unknown probability of explosion as a random v...

**Probability**

???

**Probability**

Let N,X1,Y1,X2,Y2,… be independent random variables. The random variable N takes positive integer values and has mean a and variance r. The random variables Xi are independent and identically distributed with mean b and variance s, and the random variables Yi are independ...

**Probability**

Let X be a random variable that takes non-zero values in [1,∞), with a PDF of the form fX(x)=⎧⎩⎨cx3 if x≥1, 0,otherwise. Let U be a uniform random variable on [0,2]. Assume that X and U are independent. What is the value of the constant c? c= P(X&...

**Probability**

Let U, V, and W be independent standard normal random variables (that is, independent normal random variables, each with mean 0 and variance 1), and let X=3U+4V and Y=U+W. Give a numerical answer for each part below. You may want to refer to the standard normal table. What is ...

**Statistics**

1. For the following research question, specify the parameter and give the null and alternative hypotheses. "Is there a difference in the proportions of male and female college students who smoke cigarettes? 2. For the following research question, specify the parameter an...

**Probability**

The random variable X is uniformly distributed over the interval [θ,2θ]. The parameter θ is unknown and is modeled as the value of a continuous random variable Θ, uniformly distributed between zero and one. Given an observation x of X, find the posterior di...

**Probability**

Let N be a geometric r.v. with mean 1/p; let A1,A2,… be a sequence of i.i.d. random variables, all independent of N, with mean 1 and variance 1; let B1,B2,… be another sequence of i.i.d. random variable, all independent of N and of A1,A2,…, also with mean 1 and ...

**Probability**

Let X=U+W with E[U]=m, var(U)=v, E[W]=0, and var(W)=h. Assume that U and W are independent. The LLMS estimator of U based on X is of the form U^=a+bX. Find a and b. Express your answers in terms of m, v, and h using standard notation. a=- unanswered b=- unanswered Suppose we f...

**Probability**

Caleb builds a particle detector and uses it to measure radiation from a remote star. On any given day, the number of particles, Y, that hit the detector is distributed according to a Poisson distribution with parameter x. The parameter x is unknown and is modeled as the value...

**Probability**

We have k coins. The probability of Heads is the same for each coin and is the realized value q of a random variable Q that is uniformly distributed on [0,1]. We assume that conditioned on Q=q, all coin tosses are independent. Let Ti be the number of tosses of the ith coin unt...

**probability**

The lifetime of a type-A bulb is exponentially distributed with parameter λ. The lifetime of a type-B bulb is exponentially distributed with parameter μ, where μ>λ>0. You have a box full of lightbulbs of the same type, and you would like to know wheth...

**Probability**

Let T1,T2,…,Tn be i.i.d. observations, each drawn from a common normal distribution with mean zero. With probability 1/2 this normal distribution has variance 1, and with probability 1/2 it has variance 4. Based on the observed values t1,t2,…,tn, we use the MAP rule ...

**probability**

The vertical coordinate (“height") of an object in free fall is described by an equation of the form x(t)=θ0+θ1t+θ2t2, where θ0, θ1, and θ2 are some parameters and t stands for time. At certain times t1,…,tn, we make noisy observati...

**Probability**

Let Θ be a Bernoulli random variable that indicates which one of two hypotheses is true, and let P(Θ=1)=p. Under the hypothesis Θ=0, the random variable X is uniformly distributed over the interval [0,1]. Under the alternative hypothesis Θ=1, the PDF of X i...

**Probability**

Alice has two coins. The probability of Heads for the first coin is 1/3, and the probability of Heads for the second is 2/3. Other than this difference, the coins are indistinguishable. Alice chooses one of the coins at random and sends it to Bob. The random selection used by ...

**Probability**

A defective coin minting machine produces coins whose probability of Heads is a random variable Q with PDF fQ(q)={3q2,0,if q∈[0,1],otherwise. A coin produced by this machine is tossed repeatedly, with successive tosses assumed to be independent. Let A be the event that t...

**Biology**

Why does an increase in light intensity cause the rate of photosynthesis to increase?

**Math**

Thank you Ms. Sue.

**Math**

4. Your article will be featured on the front page of the World section of the newspaper, as well as on-line. The article is to be placed in the shaded section below, which measures 4 inches wide by 9 inches long (not drawn to scale). Your editor has stated that your graph is...

**math**

Thank you Steve. That was my thinking as well. Appreciate it!!

**math**

Date US Population Jul 1, 2012 313.85 million Jul 1, 2011 311.59 million Jul 1, 2010 309.35 million Jul 1, 2009 306.77 million Jul 1, 2008 304.09 million Jul 1, 2007 301.23 million Jul 1, 2006 298.38 million Jul 1, 2005 295.52 million Jul 1, 2004 292.81 million Jul 1, 2003 29...

**Math**

Check please. Bar chart for each one because you have the values up the left side and item listed/categorized along the bottom for a more reader friendly chart for the data.

**Math**

20146/1650=12.21%

**physics**

What is the gravitational field strength at a height h above the surface of the Earth? R is the radius of the earth gR2(R+h)2 gR(R+h) g(R−h)R g(R−h)2R2 2 The instrument used for experimental determination of the value of the universal gravitational constant G is ca...

**physics**

An object is thrown upward from the edge of a tall building with a velocity of 10 m/s. Where will the object be 3 s after it is thrown? Take g=10ms−2

**Physics**

Similarities between distance and displacement similarities between speed and velocity

**Grammar**

I thought it was natural to use "her", but I guess it is a common mistake.

**Mathh**

A certain state taxes the first $400,000 in property value at a rate of 1%; all value over $400,000 is taxed at 1.75%. Find a piecewise-defined function T that specifies the total tax on a property valued at x dollars. (Simplify your answer completely.) 0.01x if 0<x<400,...

**PHYSICS**

Can someone teach us how to do b,c?

**PHYSICS(help)**

did someone how to do 3,5,6b....?

**Math**

hi

**Engineering**

Thank you. I can find it now. But can you tell me how to do 2d,e , please?

**Engineering**

yes, I know...but I don't know how to find n and eta? can you teach me how to find it?

**Engineering**

how are about b,c? can you calculate it?

**Engineering**

In the process of electrolysis, electrical power is used to separate water into oxygen and hydrogen molecules via the reaction: H2O --> H2 + ½O2 This is very much like running a hydrogen fuel cell in reverse. We assume that only the activation potential for the hydroge...

**Engineering**

Here we consider instead dissolving guns (which we will assume are pure iron) with sulfuric acid. Fe+H2SO4->FeSO4+H2 The characters realize that their hideout has been discovered by the police and they still have a last handgun that weighs 0.25 kg to dissolve. The cops will...

**Engineering**

Here we consider instead dissolving guns (which we will assume are pure iron) with sulfuric acid. Fe+H2SO4->FeSO4+H2 It is apparent that they must use an outside source of electrical power to drive the dissolution of the iron. They use a small current so that the dissolutio...

**Astronomy help**

I have already solve the problems in many time, but still cannot get the correct answer, can someone kindly help me to solve the problem, please? 1. Suppose the Moon is at a (center-to-center) distance D from Earth. Find an exact expression for the magnitude of the tidal force...

**Language arts help!!**

You don't learn anything by just copying answers.

**Physics Classical Mechanics**

You are holding a ball of mass m2 in your hand. In this problem you will solve for the upward force T⃗ that the tendon of your biceps muscle exerts to keep the forearm horizontal and the downward force F⃗ that the upper arm exerts on the forearm at the elbow joint....

**Physics Classical Mechanics**

A person of mass m2= 85.0 kg is standing on a rung, one third of the way up a ladder of length d= 3.0 m. The mass of the ladder is m1= 15.0 kg, uniformly distributed. The ladder is initially inclined at an angle θ= 35.0∘ with respect to the horizontal. Assume that t...

**Physics Classical Mechanics**

A uniform steel beam of mass m1= 300.0 kg is held up by a steel cable that is connected to the beam a distance L= 5.0 m from the wall, at an angle θ= 40.0∘ as shown in the sketch. The beam is bolted to the wall with an unknown force F⃗ exerted by the wall on t...

**Physics Classical Mechanics**

A crane is configured as below, with the beam suspended at two points l1 and l2 by each end of a cable passing over a frictionless pulley. The two ends of the cable each make an angle θ with the beam. A counterbalance object C with mass mC is fixed at one end of the beam....

**Math**

Solve for B: A=1/2(b+B) h show work. I am struggling with the above equation can someone please help? Thanks

**Physics Classical Mechanics**

A rod is lying at rest on a perfectly smooth horizontal surface (no friction). We give rod a short impulse (a hit) perpendicular to the length direction of the rod at X. The mass of the rod is 3 kg, and its length is 50 cm. The impulse is 4 kg⋅m/sec. The distance from th...

**Physics Classical Mechanics**

A solid disk 1 with radius R1 is spinning freely about a frictionless horizontal axle l at an angular speed ω initially. The axle l is perpendicular to disk 1, and goes through the center S of disk 1. The circumference of disk 1 is pushed against the circumference of anot...

**Physics Classical Mechanics**

A physical pendulum consists of a disc of radius R and mass m fixed at the end of a rod of mass m and length l . (a) Find the period of the pendulum for small angles of oscillation. Express your answer in terms of m, R, l and acceleration due to gravity g as needed (enter m fo...

**Physics Classical Mechanics**

A uniform stick of mass m and length l is suspended horizontally with end B at the edge of a table as shown in the diagram, and the other end A is originally held by hand. The hand at A is suddenly released. At the instant immediately after the release: (a) What is the magnitu...

**Physics Classical Mechanics**

A yo-yo of mass m rests on the floor (the static friction coefficient with the floor is μ). The inner (shaded) portion of the yo-yo has a radius R1, the two outer disks have radii R2. A string is wrapped around the inner part. Someone pulls on the string at an angle β...

**Physics Classical Mechanics**

A light inflexible cable is wrapped around a cylinder of mass m1 , radius R , and moment of inertia about the center of mass Ic . The cylinder rotates about its axis without friction. The cable does not slip on the cylinder when set in motion. The free end of the cable is atta...

**Physics Classical Mechanics**

A pulley of mass mp , radius R , and moment of inertia about the center of mass Ic=12mpR2 , is suspended from a ceiling. The pulley rotates about a frictionless axle. An inextensible string of negligible mass is wrapped around the pulley and it does not slip on the pulley. The...

**Physics Classical Mechanics**

A playground merry-go-round has a radius of R= 2 m and has a moment of inertia Icm= 9×103kg⋅m2 about a vertical axis passing through the center of mass. There is negligible friction about this axis. Two children each of mass m= 30kg are standing on opposite sides a...

**Physics Classical Mechanics**

A turntable is a uniform disc of mass m and radius R. The turntable is initially spinning clockwise when looked down on from above at a constant frequency f0. The motor is turned off at t=0 and the turntable slows to a stop in time t with constant angular deceleration. (a) Wha...

**History**

Mongols

**algebra 1**

thanks

**algebra 1**

please show me how to solve questions like the these step by step so I can be prepared to solve the rest of my homework thank you

**algebra 1**

write the equation in standard form. Y + 1 = X + 2

**maths**

20

**Solar Energy Please Help**

postimg org/image/kylqxalt7/ Try this put a dot after 'postimg'

**Solar Energy Please Help**

courses edx org/c4x/DelftX/ET3034TUx/asset/Week5_Specturm png This is the image's url, replace the spaces with dots

**Solar Energy Help ASAP**

78.125 & 13

**Solar Energy Help ASAP**

first answer is 25

**Solar Energy Help ASAP**

users . encs. concordia. ca/~mojtaba/ ELEC425- assignment4- solutions . pdf edit the spaces

**physical science**

test it

**Quantum Physics**

7c, t=pi --> -1,0,0

**Quantum Physics**

6c can be calculated by answer to 6b - 1

**8th grade science**

Thank You so much Ms. Sue :D

**8th grade science**

How does altitude affect the freezing, melting and boiling points of water?

**SS**

The political movement that brought Africans together in the 1950s was known as ________. a. imperialism b. salt trade c. colonialism d. Pan-Africanism Enslaved Africans from West Africa traveled across the Atlantic Ocean to European Colonies in the Americas by way of the ____...

**Biology**

a

**MATH**

14

**Please help CHEM**

What is the Kc for the following equilibrium at 500∘C, N2(g)+3H2(g)⇌2NH3(g) [H2] = 0.50M , [N2] = 0.50M , [NH3] = 2.0M ?

**CHM**

A sample of gas has an initial volume of 2.4 L at a pressure of 855 mm Hg and a temperature of 298K. If the gas is heated to a temperature of 387 K and expanded to a volume of 4.1 L, what is its final pressure in mm of mercury?

**Math**

One popular ride at carnivals is the Roundabout, which works in the following manner. Riders stand on the inside edge of a circle, with their backs against a wall mounted on the edge of the circle. The wheel begins to spin. Once it is spinning fast enough the whole wheel tilts...

**chemistry**

You will be presented with three crystallographic directions drawn in a unit cell. Please write the identity of the direction in the space provided below each picture. Use the correct form of brackets for describing a direction, and leave no spaces between numbers. If you must...

**chemistry**

What is the approximate ratio in conductivity of silicon doped with 37 ppm to silicon doped with 5 ppm

**chemistry**

A comparison of density values obtained by X-ray diffraction reveals that the percentages of vacant sites in aluminum (Al) are 0.0700% at 923 K and 0.0090% at 757 K. Given this data, determine the number of vacant sites per cm3 at 550 K. Express your answer as vacancies/cm3. 7...

**chemistry**

The skeletal structures of the two amino acids, glycine and lysine, are given below along with the values of the relevant acid dissociation constants (pKa). (a) For an aqueous solution of glycine alone, calculate the value of pH at which the ratio of the concentration of neutr...

**heeeeeeeelp math**

wrong there is other max but wolfram dpoesnt give excct val

**Chemistry**

wrong

**chemistry**

What should be the pH of the aqueous layer to extract caffeine? There are three aqueous solutions that you may choose from. Answer A. pH >14, using 2.5 M NaOH (aq) B. pH 1, using 0.1 M HCl (aq) C. pH 6.2, using 0.1 M NaHCO3 (aq)

**chemistry**

What should be the pH of the aqueous layer to extract caffeine? There are three aqueous solutions that you may choose from. Answer A. pH >14, using 2.5 M NaOH (aq) B. pH 1, using 0.1 M HCl (aq) C. pH 6.2, using 0.1 M NaHCO3 (aq)

**physics**

While passing a slower car on the highway, you accelerate uniformly from 18.5 m/s to 29.3 m/s in a time of 12.0 s. How far do you travel during this time?

**math **

A hot water heater measures 20" in diameter. What is the area of a metal base for the water heater, assuming a four-inch overhang for the base beyond the edge of the heater? (Round to the nearest tenth.)

**physics**

how?

**math**

4^6=4096 1/5 of 4096 is around 819 or 820 try it

**Mathematics**

yes

**spanish**

como te llamas

**Geometry**

441

**Geometry**

59

**Math (Geometry)**

441

**physics**

The convex lens of a copy machine has a focal length of 22.0 cm. A letter to be copied is placed 37.0 cm from the lens. (a) How far from the lens is the copy paper? (b) How much larger will the copy be?

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