# qwerty

Most popular questions and responses by qwerty-
## Probability

In parts 1, 3, 4, and 5 below, your answers will be algebraic expressions. Enter 'lambda' for and 'mu' for . Follow standard notation. 1. Shuttles bound for Boston depart from New York every hour on the hour (e.g., at exactly one o'clock, two o'clock,

*asked on April 29, 2014* -
## Probability

Oscar has lost his dog in either forest A (with probability 0.4) or in forest B (with probability 0.6). If the dog is in forest A and Oscar spends a day searching for it in forest A, the conditional probability that he will find the dog that day is 0.25.

*asked on February 13, 2015* -
## Probability

For each of the following statements, determine whether it is true (meaning, always true) or false (meaning, not always true). Here, we assume all random variables are discrete, and that all expectations are well-defined and finite. Let X and Y be two

*asked on March 4, 2014* -
## Probability

Random variables X and Y are distributed according to the joint PDF fX,Y(x,y) = {ax,0,if 1≤x≤2 and 0≤y≤x,otherwise.} 1. Find the constant a. 2. Determine the marginal PDF fY(y). (Your answer can be either numerical or algebraic functions of y). For

*asked on March 18, 2014* -
## Probability

Consider 10 independent tosses of a biased coin with the probability of Heads at each toss equal to p , where 0 < p < 1 . 1. Let A be the event that there are 6 Heads in the first 8 tosses. Let B be the event that the 9th toss results in Heads. Find P(B|A)

*asked on February 28, 2014* -
## 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

*asked on April 27, 2014* -
## Probability

The newest invention of the 6.041x staff is a three-sided die. On any roll of this die, the result is 1 with probability 1/2, 2 with probability 1/4, and 3 with probability 1/4. Consider a sequence of six independent rolls of this die. 1. Find the

*asked on February 20, 2015* -
## Probability

Consider the communication network shown in the figure below and suppose that each link can fail with probability p. Assume that failures of different links are independent. Assume that p=1/3. Find the probability that there exists a path from A to B along

*asked on February 16, 2015* -
## 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

*asked on April 21, 2014* -
## Probability

Consider a sequence of independent tosses of a biased coin at times k=0,1,2,…,n. On each toss, the probability of Heads is p, and the probability of Tails is 1−p. A reward of one unit is given at time k, for k∈{1,2,…,n}, if the toss at time k

*asked on February 25, 2015* -
## Probability

The newest invention is a three-sided die. On any roll of this die, the result is 1 with probability 1/2, 2 with probability 1/4, and 3 with probability 1/4. Consider a sequence of six independent rolls of this die. 1. Find the probability that exactly two

*asked on February 23, 2014* -
## Probability

All ships travel at the same speed through a wide canal. Each ship takes days to traverse the length of the canal. Eastbound ships (i.e., ships traveling east) arrive as a Poisson process with an arrival rate of ships per day. Westbound ships (i.e., ships

*asked on April 29, 2014* -
## Chemistry

An equilibrium mixture contains 0.250 mol of each of the products (carbon dioxide and hydrogen gas) and 0.200 mol of each of the reactants (carbon monoxide and water vapor) in a 1.00-L container. CO(g) + H2O(g) CO2(g)+ H2(g) How many moles of carbon

*asked on March 3, 2013* -
## Probability

You roll two five-sided dice. The sides of each die are numbered from 1 to 5. The dice are “fair" (all sides are equally likely), and the two die rolls are independent. Part (a): Event A is “the total is 10" (i.e., the sum of the results of the two die

*asked on February 13, 2015* -
## Probability

Each one of n persons, indexed by 1,2,…,n, has a clean hat and throws it into a box. The persons then pick hats from the box, at random. Every assignment of the hats to the persons is equally likely. In an equivalent model, each person picks a hat, one

*asked on February 20, 2015* -
## Probability

Before leaving for work, Victor checks the weather report in order to decide whether to carry an umbrella. On any given day, with probability 0.2 the forecast is “rain" and with probability 0.8 the forecast is “no rain". If the forecast is “rain",

*asked on February 13, 2015* -
## History

Civilizations of the Americas Practice 1. Which of the following statements explains why the Aztec continually waged war? A. The Aztec needed prisoners of war to work the land. B. The Aztec needed more people to help build their pyramids. C. The Aztec

*asked on April 14, 2019* -
## Astronomy

A roughly spherical asteroid with a diameter of 1 km, and a mean density of 4 g/cm^3, hits the Earth with a relative speed 1.5 times the orbital velocity of the Earth. Compute the amount of energy released upon the impact. Compare that with the energy

*asked on April 25, 2014* -
## Logic

Consider a propositional language with three propositional constants - mushroom, purple, and poisonous - each indicating the property suggested by its spelling. Using these propositional constants, encode the following English sentences as Propositional

*asked on October 6, 2014* -
## Big Data

Imagine there are 100 baskets, numbered 1,2,...,100, and 100 items, similarly numbered. Item i is in basket j if and only if i divides j evenly. For example, basket 24 is the set of items {1,2,3,4,6,8,12,24}. Describe all the association rules that have

*asked on October 6, 2014* -
## Probability

The random variables X1,..,Xn are independent Poisson random variables with a common parameter Lambda . Find the maximum likelihood estimate of Lambda based on observed values x1,...,xn.

*asked on April 21, 2014* -
## Probability

Let Sn be the number of successes in n independent Bernoulli trials, where the probability of success for each trial is 1/2 . Provide a numerical value, to a precision of 3 decimal places, for each of the following limits. 1. lim P (n/2 - 20 < Sn < n/2 +

*asked on April 21, 2014* -
## Chemistry

The units of parts per million (ppm) and parts per billion (ppb) are commonly used by environmental chemists. In general, 1 ppm means 1 part of solute for every 106 parts of solution. (Both solute and solution are measured using the same units.)

*asked on January 23, 2019* -
## Genetics

In Drosophila melanogaster, the genes for purple eyes (pr) and curved wings (c) are on the same chromosome. The recombination frequency between pr and c is roughly 20%. Both the purple eyed and curly winged phenotypes are recessive to the wild-type (+)

*asked on March 21, 2013* -
## 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 as a conservative value

*asked on April 21, 2014* -
## Probability

Alice plays the following game with Bob. First, Alice randomly chooses a set of 4 cards out of a 52-card deck, memorizes them, and places them back into the deck. (Any set of 4 cards is equally likely.) Then, Bob randomly chooses 8 cards out of the same

*asked on February 23, 2014* -
## Chemistry

For each of the following, enter the number of covalent bonds that the atom can form: (A) One atom of carbon (B) One atom of sulfur (C) One atom of nitrogen with no net charge (D) One atom of nitrogen with positive net charge (E) One atom of oxygen with no

*asked on March 7, 2013* -
## Probability

Let A,B,C be three events and let X=IA, Y=IB, Z=IC be the associated indicator random variables. We already know that X⋅Y is the indicator random variable of the event A∩B. In the same spirit, give an algebraic expression, involving X, Y, Z for the

*asked on March 7, 2015* -
## Big Data

Suppose our input data to a map-reduce operation consists of integer values (the keys are not important). The map function takes an integer i and produces the list of pairs (p,i) such that p is a prime divisor of i. For example, map(12) = [(2,12), (3,12)].

*asked on October 6, 2014* -
## 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

*asked on April 21, 2015* -
## Social Studies

Between 1820 and 1860 which two issues dominated United States politics? (1 point ) a.)Trust and economic growth b.)National security and law c.)The environment and states' rights"""" d.)Westward expansion and slavery

*asked on October 23, 2018* -
## Probability

A fair coin is tossed repeatedly and independently. We want to determine the expected number of tosses until we first observe Tails immediately preceded by Heads. To do so, we define a Markov chain with four states, {!@#$%^&,HT}, where S is a starting

*asked on May 19, 2015* -
## Probability

We are given the following statistics about the number of children in the families of a small village. There are 100 families: 10 families have no children, 40 families have 1 child each, 30 families have 2 children each, 10 families have 3 each, and 10

*asked on April 29, 2014* -
## Probability

Alice has five coins in a bag: two coins are normal (i.e., fair with one face Heads and the other face Tails), two are double-headed (i.e., both sides are Heads), and the last one is double-tailed (i.e., both sides are Tails). She reaches into the bag and

*asked on March 7, 2014* -
## Astronomy

The luminosity of the Sun is 4*10^33 erg/s, and its radius is 7*10^10 cm. What is the Sun's effective temperature? Please enter your answer in units of Kelvin. What is the Sun's effective temperature? Please enter your answer in units of Kelvin. -

*asked on April 29, 2014* -
## Probability

You are given the set of letters ( A, B, C, D, E ). What is the probability that in a random five-letter string (in which each letter appears exactly once, and with all such strings equally likely) the letters A and B are next to each other?

*asked on February 23, 2014* -
## Chemistry

1)Buttermilk has 9 grams of protein and 12 grams of carbohydrate per cup (237ml). Estimate the concentration in mol/L of protein using the fact that the average protein is 300 amino acids long and the average amino acid has a mass of 110 amu. 2)Lactose

*asked on October 10, 2013* -
## Probability

Consider three random variables X, Y, and Z, associated with the same experiment. The random variable X is geometric with parameter p∈(0,1). If X is even, then Y and Z are equal to zero. If X is odd, (Y,Z) is uniformly distributed on the set

*asked on March 10, 2015* -
## Logic

Given the premises (p ⇒ q) and (r ⇒ s), use Propositional Resolution to prove the conclusion (p ∨ r ⇒ q ∨ s). Proof takes 8 steps including the premises and the goal.

*asked on October 23, 2014* -
## Big Data

Suppose ABC is a frequent itemset and BCDE is NOT a frequent itemset. Given this information, we can be sure that certain other itemsets are frequent and sure that certain itemsets are NOT frequent. Other itemsets may be either frequent or not. Which of

*asked on October 6, 2014* -
## 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

*asked on April 21, 2015* -
## Probability

A player is randomly dealt a sequence of 13 cards from a standard 52-card deck. All sequences of 13 cards are equally likely. In an equivalent model, the cards are chosen and dealt one at a time. When choosing a card, the dealer is equally likely to pick

*asked on February 23, 2014* -
## Astronomy

One possible energy source for the mysterious object you've just discovered is the fusion of hydrogen to form carbon-12 (the most common and stable isotope of Carbon). Hydrogen has an atomic mass of 1.00794 u, while carbon has an atomic mass of 12.010 u.

*asked on April 28, 2014* -
## history

why is the significance of the mandate of heaven in the shang and zhou dynasty? i googled it and browsed around wiki what i gathered was it justified the kings actions and made it so people who werent of royal birth eligable of being a ruler... can anyone

*asked on September 14, 2008* -
## Astronomy

A quasar is observed at a redshift of z=1, which corresponds to a comoving radial distance of 3 Gpc. Its observed bolometric flux is 10^{-12} erg/cm^2/s. An interacting companion galaxy is seen 4 arcsec apart in projection. What is the bolometric

*asked on June 19, 2014* -
## Science

How could the development of a smart grid help protect the environment? a. a smart grid uses only renewable energy sources b. a smart grid burns fossil fuels without producing pollution c. a smart grid connects nonrenewable energy sources, making them

*asked on November 18, 2016* -
## Probability

Uncle Henry has been having trouble keeping his weight constant. In fact, during each week, his weight changes from the beginning of the week to the end of the week by a random amount, uniformly distributed between -0.5 and 0.5 pounds. Assuming that his

*asked on May 13, 2014* -
## Probability

Consider the following joint PMF of the random variables X and Y: pX,Y(x,y)={1/72⋅(x2+y2),if x∈{1,2,4} and y∈{1,3}, 0, otherwise}. 1. P(Y

*asked on March 7, 2014* -
## search engine results

What is the significance when Googling gives you web site addresses that have tor dot onion or onion dot rip? I have never seen URL's formatted like that before just now.

*asked on February 25, 2019* -
## Chemistry

The following questions concern the iconic Nestle Toll House Chocolate Chip Cookie recipe, shown below: 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter or margarine, softened 3/4 cup granulated sugar 3/4 cup packed brown

*asked on October 10, 2013* -
## Astronomy

The star Polaris has a surface temperature of roughly 6500 K and a radius of approximately 50 solar radii. Find the luminosity of Polaris in terms of the Sun's luminosity.

*asked on June 24, 2014* -
## Astronomy

The current peak wavelength of the CMB corresponds to a blackbody of temperature 2.74K. What was the peak wavelength of the CMB when it was emitted? The current redshift of the CMB is z=1100. Give your answer in microns. Which waveband regime is this?

*asked on June 24, 2014* -
## history

compare and contrast two ancient civilizations. i had the choice between -indus -mesoamerica -egypt -mesopotamia -china haung he river i think im going to write about egypt and mesopotamia since they have alot on them... for now all i have to write is an

*asked on September 18, 2008* -
## geography

which of the following was NOT a characteristic of native american societies during the mississippian period

*asked on October 16, 2019* -
## Logic

Use Propositional Resolution to show that the clauses {p, q}, {¬p, r}, {¬p, ¬r}, {p, ¬q} are not simultaneously satisfiable. Proof takes 8 steps including the premises and the goal.

*asked on October 23, 2014* -
## Probability

Uncle Henry has been having trouble keeping his weight constant. In fact, during each week, his weight changes from the beginning of the week to the end of the week by a random amount, uniformly distributed between -0.5 and 0.5 pounds. Assuming that his

*asked on May 26, 2015* -
## Probability

A fair, 6-sided die is rolled 6 times independently. Assume that the results of the different rolls are independent. Let (a1,…,a6) denote a typical outcome, where each ai belongs to {1,…,6}. Find the probability that the results of the 6 rolls are all

*asked on March 7, 2015* -
## Astronomy

The luminosity of the Sun is 4*10^33 erg/s, and its radius is 7*10^10 cm. What is the Sun's effective temperature? Please enter your answer in units of Kelvin.

*asked on May 6, 2014* -
## Probability

We are told that events A and B are conditionally independent, given a third event C, and that P(B∣C)>0. For each one of the following statements, decide whether the statement is “Always true", or “Not always true." A and B are conditionally

*asked on March 8, 2015* -
## Physics

Which of the following processes is used in order to fabricate monocrystalline silicon? Note that more than one correct answer is possible. The Czochralski process Silicon ribbon process The float-zone process The silicon casting process

*asked on October 8, 2014* -
## Probability

To get a complete collection of stamps, Ann needs to have 5 specific (and different) kinds of stamps, denoted by k1,…,k5. She starts out with no stamps. She then receives 5 stamps randomly from a lottery. Each of these 5 stamps has probability 1/5 of

*asked on March 7, 2014* -
## Probability

Let X and Y be independent random variables, each uniformly distributed on the interval [0,2]. Find the mean and variance of XY. E[XY]= - unanswered var[XY]= - unanswered Find the probability that XY≥1. Enter a numerical answer. P(XY≥1)= -

*asked on May 26, 2015* -
## Probability

Fred is giving away samples of dog food. He makes visits door to door, but he gives a sample away (one can of dog food) only on those visits for which the door is answered and a dog is in residence. On any visit, the probability of the door being answered

*asked on April 29, 2014* -
## Probability

Consider three random variables X, Y, and Z, associated with the same experiment. The random variable X is geometric with parameter p∈(0,1). If X is even, then Y and Z are equal to zero. If X is odd, (Y,Z) is uniformly distributed on the set

*asked on March 7, 2015* -
## Chemistry

The following questions concern the iconic Nestle Toll House Chocolate Chip Cookie recipe, shown below: 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter or margarine, softened 3/4 cup granulated sugar 3/4 cup packed brown

*asked on October 10, 2013* -
## Statics

You have a stainless steel hollow rod (E=193GPa,ν=0.29) that has an inner radius r of 1.2cm, a wall thickness t of 0.7mm, and a length L of 5cm. Calculate the critical loads, in kN, for local buckling and Euler bucking (Pcr,local and Pcr,Euler,

*asked on October 23, 2014* -
## 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

*asked on April 21, 2015* -
## Astronomy

Imagine that you have found an object out in space. When you use the inverse square law to compute its luminosity, you get a ridiculously large value. You therefore suspect that relativistic beaming is at work - the radiation is coming from a jet traveling

*asked on May 11, 2014* -
## Algebra

You borrow $40 from your sister. To repay the loan, you pay her $5 a week. Write a linear equation to model the situation and check with unit alalysis.

*asked on November 13, 2011* -
## Physics

The current density of an ideal p-n junction under illumination can be described by: J(V)=Jph−J0(e^qV/kT−1) where Jph is the photocurrent density, J0 the saturation current density, q the elementary charge, V the voltage, k the Boltzmann's constant,

*asked on October 3, 2014* -
## Physics

The width of the space charge region at a p-n junction is reduced by applying a voltage bias over the p-n junction. What is the correct statement on both the bias voltage and the p-n junction? The voltage is a forward bias and the diffusion of the majority

*asked on October 3, 2014* -
## Probability

A dedicated professor has been holding infinitely long office hours. Undergraduate students arrive according to a Poisson process at a rate of per hour, while graduate students arrive according to a second, independent Poisson process at a rate of per

*asked on May 13, 2014* -
## Astronomy

Rank the following hypothetical planets -- all of which have the same total mass and same radius -- from lowest moment of inertia to highest moment of inertia: 1) A uniform sphere of mixed up rock and iron 2) A hollow sphere 3) A rocky planet with an iron

*asked on April 21, 2014* -
## Physics

Let's assume that solar light reaches a silicon solar cell with an angle of incidence of θi=0o. For simplicity, let's consider the refractive index of silicon to be nSi=3.5. The refractive index of air is nair=1. What percentage of light would be lost due

*asked on October 3, 2014* -
## Physics

A solar cell with dimensions 12cm x 12cm is illuminated at standard test conditions. The cell presents the following external parameters: Voc=0.8V,Isc=3A,Vmp=0.75V,Imp=2.5A Calculate the fill factor in percentage [%]: Calculate the efficiency (in %):

*asked on October 3, 2014* -
## Material Sciences

The molar crosslink density of a rubber is measured to be 468mol/m3 for a temperature T=300K. What is the Young's modulus of the rubber in MPa? What happens to the modulus of the rubber when the temperature is increased? Young's modulus decreases Young's

*asked on September 28, 2014* -
## Probability

A group of 90 students is to be split at random into 3 classes of equal size. All partitions are equally likely. Joe and Jane are members of the 90-student group. Find the probability that Joe and Jane end up in the same class.

*asked on February 23, 2014* -
## Probability

Let X be a random variable that takes non-zero values in [1,∞), with a PDF of the form fX(x)=⎧⎩⎨cx3,0,if x≥1,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= -

*asked on April 21, 2015* -
## Mechanical Behavior of Materials

What is the exact strain energy per unit length of an edge dislocation for a material that has a Young's modulus E of 50GPa, a Burger's vector b of 0.25nm, a dislocation density ρ of 108cm−2, and a Poisson's ratio ν of 0.3? Uedge (in J/m): What is the

*asked on November 23, 2014* -
## Statics

Calculate the elastic buckling collapse stress (the compressive strength), σ∗el, for an open-cell polystyrene foam with a relative density of 0.1. (Es for polystyrene = 3.5GPa). Recall that C2=0.05. Give the results in MPa. σ∗el (in MPa): The energy

*asked on October 23, 2014* -
## Materials Science

A linear elastic, isotropic epoxy resin with elastic modulus, E=2GPa, and Poisson’s ratio, ν=0.3, is loaded by the following stress state: σ=⎡⎣10 5 0 5 −20 0 0 0 0⎤⎦MPa Give numerical values for all strain components in the corresponding

*asked on October 1, 2014* -
## Materials Science

A compression bar, having a square cross section of side length b, must support a compressive load of magnitude W, uniformly distributed over the bar cross section. The bar is made of two segments connected by a glued joint along plane pq, which is at an

*asked on October 10, 2014* -
## Big Data

The edit distance is the minimum number of character insertions and character deletions required to turn one string into another. Compute the edit distance between each pair of the strings he, she, his, and hers. Then, identify which of the following is a

*asked on October 6, 2014* -
## chem

If the KCLO3 were not completely decomposed, would your calculated values for percent oxygen in KCLO3 be too high, too low or unaffected?

*asked on November 1, 2017* -
## Biology

Dopamine is a neurotransmitter—a chemical released by nerve cells to send signals to other nerve cells. Activities like sex and gambling increase the levels of dopamine released within the brain. The highly addictive drugs cocaine and methamphetamine

*asked on March 7, 2013* -
## Materials Science

A cylindrical pressure vessel, with a diameter of 40cm and a wall thickness of 10mm is made of steel (isotropic, with Young’s modulus = 200GPa; Poisson’s ratio = 0.28) and is pressurized to 20MPa. The longitudinal and hoop stresses in the wall, σl and

*asked on October 1, 2014* -
## Astronomy

A galaxy is receding away from us with a recession velocity of 100,000 km/s. What is the distance to this galaxy? What is the redshift z of this galaxy?

*asked on June 24, 2014* -
## Astronomy

Imagine that you are an astronomer, and you are planning to do a survey to find new brown-dwarf stars. You need to calculate how sensitive your search needs to be (and hence how big a telescope you will need and how long the survey will take). You want to

*asked on May 11, 2014* -
## Probability

Let X and Y be normal random variables with means 0 and 2, respectively, and variances 1 and 9, respectively. Find the following, using the standard normal table. Express your answers to an accuracy of 4 decimal places. 1. P(X>0.75)= 2. P(X≤−1.25)= 3.

*asked on March 18, 2014* -
## Astronomy

What is the estimated total lifetime for a star with mass 0.7 Msun ? (in billions of year)

*asked on March 4, 2014* -
## 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:

*asked on April 21, 2015* -
## Statics

You have 1kg of aluminum (E=69GPa) to make a cylindrical tube with a high Euler buckling load. The tube must have a length L of 0.5m. You can either make a solid tube, or a thin walled tube with a wall thickness, t=0.5cm. The density of aluminum is

*asked on October 23, 2014* -
## 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

*asked on April 21, 2015* -
## Probability

A dedicated professor has been holding infinitely long office hours. Undergraduate students arrive according to a Poisson process at a rate of λu=3 per hour, while graduate students arrive according to a second, independent Poisson process at a rate of

*asked on May 26, 2015* -
## Economy

What is the cost of producing 100 units of output for a firm with a production function given by !@#$%^&,l)=10(min(2k,l))^0.5? Assume that r=20 $/unit and w=10 $/unit

*asked on February 1, 2015* -
## Statics

Compare the Young's modulus E∗ of two open-cell foams. Which Young's modulus is higher? Recall that C1=1. 1. polystyrene: (Es∼3.5GPa), ρ∗/ρs=0.3 2. Al 7075-T651: (Es∼72GPa), ρ∗/ρs=0.1 E∗PS (in GPa): E∗Al (in GPa): Select the correct

*asked on October 23, 2014* -
## Statics

A cantilever beam, made of a material with a Young's modulus, E with a rectangular cross section with a moment of inertia I, is under a uniformly distributed load, q, across the length L of the cantilever at a point load P at the free end of the

*asked on October 23, 2014* -
## Probability

Suppose that you move to a new house and you are 10% sure that your new house's phone number is 561290. To verify this, you use the house's phone to dial 561290, obtain a busy signal, and conclude that this is indeed your phone number. (Suppose that you

*asked on May 13, 2014* -
## Astronomy

Choose one answer for each question How old is the universe? 6,000 years old 380,000 years old 13.8 billion years old 13.8 million years old A parsec is: Longer than a light year The distance between the Earth and the Sun Approximately 3x10^24 cm None of

*asked on April 29, 2014* -
## Probability

Consider a Markov chain X0,X1,X2,… described by the transition probability graph shown below. The chain starts at state 1; that is, X0=1. Find the probability that X2=3. P(X2=3)= - unanswered Find the probability that the process is in state 3

*asked on May 26, 2015*