Statistics Definition and 998 Threads

Homework Statement Hi all. I thought about this earlier today. Let's say I toss a dice three times, and the outcome is 2, 4 and 5. Is the mean (2+4+5)/3 or (2+4+5)/6? The reason why I am asking is that we can look at the mean as a weighted average of the probability of getting each...

Homework Statement From the data: x=-5 -4 -3 -2 -1 0 1 2 3 4 5 y= 1 5 4 7 10 8 9 13 14 13 18 These values are in a table, ie -5 corresponds to 1, -4 to 5 and so on. I have to find: Sxx=Sum of [x(i) - mean of x]^2 Sxy=Sum of [x(i) - mean of x][y(i) - mean of y] Im...

Homework Statement Hi all. Lets say I have two variables yk and xk. I also have two mean values given by: <y_k^2> = \frac{1}{N}\sum_1^N{y_k^2} \quad \text{and} \quad <x_k^4> = \frac{1}{N}\sum_1^N{x_k^4}. Now I am looking at the expression (<xk4> <yk2>)1/2. Question: Is it correct that...

Homework Statement I have a table with a data set #, and 2 variables (W and P) with values in the table. Homework Equations The equation (which I don't know what it means) says V= (summation with n on top and i=1 below Wi X Pi)/(summation with n on top and i=1 on bottom X Pi) The...

"If X is non-negative, then E(X) = Integral(0 to infinity) of (1-F(x))dx, where F(x) is the cumulative distribution function of X." ============================ First of all, does X have to be a continuous random variable here? Or will the above result hold for both continuous and...

Homework Statement Hi all. At a poll in America, where 1000 people have been asked, 480 people said that they would vote yes on proposition A (it is a fictive proposition), and of course 520 people said they would vote no on proposition A. I have to find the probability that proposition A...

Hey folks, I need a good intro to statistics book that will take me through the 'statistics equivalent' of a Cal I, II and III course (US). One that starts with a good foundation, and proceeds up to a pretty advanced level. I have just finished a PhD in physics, so my math is 'good', but...

Homework Statement Suppose the random variable X has a N(5,25) dsitribution and Y has a N(2,16) distribution and that X and Y are independent. Find a random variable F that is a function of both X and Y such that F has a F-distribution with parameters (1,2), i.e. F(1,2). Homework...

I had a MCQ exam today. 90 Questions with 4 alternatives. I need help calculating my chances of passing (which should be really small). I know 3 of my answers are correct. I gambled on the rest. Also, please calculate the chance of passing, assuming that my guesses were a little more...

If I flip two coins at once and don't care which one is heads in the case of a head and a tail, how many degrees of freedom are there?

Are spontaneous and stimulated emission selected by a Boltzmann's statistics ? Consider 2 levels(m,n) oscillators in thermal equilibrium with Einstein's coefficients Amn (spontaneous emission), Bmn (stimulated emission), Bnm (absorption) and r(f) the energy density at the frequency f (black...

Probablity & Statistics: I need some help, but not in the way you're thinking :) Homework Statement Well, I really should be getting on with my work. You see I do what's called Distance Education (I do my work from home via the internet) because I find it difficult to learn in a classroom...

Homework Statement Y is the larger score showing when two dice are thrown Calculate E(Y) Homework Equations Presume the dice are fair The Attempt at a Solution Hmm not sure. I've listed combinations of throw events on paper but I don't think that will help. Y can never be 1. Y...

Definition: Consider a set of random variables X1,X2,...,Xn, the "order statistics" are the same random variables arranged in increasing (actually nondecreasing) order, i.e. X(1)<X(2)<...<X(n) After reading a few more paragraphs, I immediately ran into deep confusion because I cannot make any...

I'm in my 4th+ year of grad school in physics, working in the field of astrophysics. I've never taken an actual statistics course, and I'm starting to see the need for one - at the moment, I get all my statistics knowledge from Numerical Recipes. I do a lot of traveling for my research, so I...

This equation comes out of deriving the canonical partition function for some system. However, the question is more math based. I am having trouble understanding the simplification that was performed in the text: ∑ from N=0 to M of: (M!exp((M-2N)a))/(N!(M-N)!) supposedly becomes...

[FONT="Century Gothic"]I was just doing some revision and came across a sticky thought - Suppose you got two appraisers for 9 car damages and both give different prices for the repair. Would the samples be independent or paired? I reckon it's paired but I can't put a reasoning behind it! And...

Boltzmann statistics -- finding the number of particles Homework Statement A column of water contains fine spherical metal particles of radius 2 x10-8m, which are in thermal equilibrium at 25C. If there are 1000 particles per unit volume at a given height, how many particles would be found...

Bonus Question on Extra Credit work... How can I do this, where do I start? I haven't taken stats before so I'm just curious to see if someone could show me how: A study considered risk factors for HIV infections among IV drug users. It found that 40% of users who had less than or...

Homework Statement If 100 students take a quiz, use chebyshev's theorem to predict the number of students plus and minus 2 standard deviations from the mean. Homework Equations 1-1/k^2 where k is standard deviations The Attempt at a Solution I think its 75, but I'm not sure...I'm just...

Homework Statement Suppose that 40 and 90 are two measurements of a population data set and that their z-scores are -2 and 3, respectively. Using only this information, is it possible to determine the population's mean and standard deviation? If so, find them. If not, explain why it's not...

Probability and Statistics Questions! Hey everyone, I've got a Statistics project due on Wednesday and I've got it all pretty much done except for a couple of questions. The ones I've got a problem with are in bold. Question 1. Airlines usually over-book the seats on an aircraft by a...

I've been reading some about Bayesian statistics, and am a little confused. I never really covered Bayesian stuff as an undergrad, and am now a physicist, so I haven't had to learn it. I have been trying to think of things in terms of more interesting examples than the trivial coin flipping...

I am wondering how one would go about solving a problem such as this. Lets say all schools compete in a competition where students are awarded a score from 0 to 5. It has been shown that the chances of a student receiving a 5 are 10%, a 4, 20% and a 3 are 25%, and below a 3 are 45% Each school...

In a particular book I'm readin on Bose-statistics it metions having a system with two bosons and a large number of energy levels for which the two bosons can occupy. 0, e,2e,3e,4e etc.. It then says the total energy of a quantum state is E_{ij} = e_i + e_j and that there is only one quantum...

I have studied a measurement 2(+0.9 error(written in superscript) and -0.1 error(written in subscript)) in a book that gives statistical value of difefrent parameters . What does this measurement implies. As a normal statistical error is written as (2 +-0.9). For e.g 2-0.1+0.9

Anybody know much about admission statistics for graduate studies at the Institute for Strings, Cosmology and Astroparticle Physics at Columbia University? Curious to know what admission rate is and what are the stats of students typically admitted. Thanks.

I am working on statistics assignment and since statistics is not my primary field of studies I have difficulties with it. can someone please help me out?? I did stem and leaf display which I think looks OK but am not sure. Homework Statement The following data represent the weights (in...

The problem in question is as follows: Find themargin of error for the given values of c, s, and n. where c is the confidence interval, s is the sample standard deviation and n is the number of objects. c=0.65 s= 1.5 n=50 the formula: E= (zc s) / n^.5 Level of Confidence Chart...

In my country, there is no system of credit transfer. The only collage that teaches Physics is one of the University Known as "Tribhuwan University". The same university also has program of M.Sc. Statistics. I'm doing job for pocket money and for study. My job and study both begin at the same...

QUES: the yield of a chemical process is bieng studied. the past 5 days of plant operation have resulted in :91.6, 88.75, 90.08, 89.95, 91.3. Find a 95% two-sided confiendce interval. Thanks folks

Ok, I know this problem is below everything on this forum, but I am an English major with no math skills and I'm REALLY stuck. This question is as follows: 1)Assume that the number of items borrowed per person per year in a library is normally distributed with a mean of 87 and a standard...

Homework Statement I have two dice, let X and Y denote (rspectively) min and maximum of the number of spots showing on the two die. Determine E(Y|X=x) for 1 <= x <=6. Homework Equations Basically all I need to do is work out E(Y| x=1), E(Y|x=2) and so on until x=6. The reason I am...

Homework Statement The Warren County Telephone Company claims in its annual report that “the typical customer spends $60 per month on local and long distance service.” A sample of 12 subscribers revealed the following amounts spent last month. $64 $66 $64 $66 $59 $62 $67 $61 $64 $58 $54...

Anyone good with statistics?? I've conducted an experiment looking at phonetic symbolism in Japanese words. Thirty participants listened to 40 Japanese words and had to choose out of a choice of two possible English translations which one they thought was the correct answer. I'm trying to...

Anyone good with statistics?? I've conducted an experiment looking at phonetic symbolism in Japanese words. Thirty participants listened to 40 Japanese words and had to choose out of a choice of two possible English translations which one they thought was the correct answer. I'm trying to...

A random variable X is gamma distributed with a=3, b=2 (alpha/beta). Determine the probability that 1\leqX\leq2 The first thing I did was plug a & b into the gamma distribution formula 1/(b^a \Gammaa * x^(a-1) * e^(-x/b) Which I ended up with 1/16(x^2 * e^(-x/2) Which I then though...

Hey everyone! I had the following problem on mt test & still can't figure out how to do it. Please help me understand it. Question: A computer has a 32-bit register. The current drawn from the power supply is i = 0.1 + 0.05k(micro amperes), where k is the number of 1's in the register...

hi :) you may remember me as the girl who drew a comicbook featuring a mathematician superhero for her nerdlove boyfriend as a valentine's day present. well, now his birthday is coming up, and I'd like to bake him a math-themed cake. I was wondering if any of you fine quantitative types...

Here is the scenario. Picture three people standing at a playground watching the children play. The first is grouchy and sees all the busy activity as stressful noise. The second person is in a good mood and sees the child play as relaxing and fun. The third person is full of anxiety and sees...

Can anyone recommend a good book for first year statistics. I'm taking a business stat course and the book for it has absolutely no depth to it. Nothing is derived or really explained from a mathmatical standpoint. This is one of those classes where you just do a bunch of plug and chug...

Hello all - I have a question I hope can be answered here. While I love Math, I know that there are very few jobs available with a BS/MS in pure Math. After taking a few Stats courses, I realized I can definitely make a career out of being a statistician. I already do the statistics for a...

Hello! In my course of solid states physics we use the fermi-dirac statistics for a free electron gas in metals. The fermi wave length of the electrons is about 1 Angström. Now, the wavelength may be intepreted as something as a coherence range - the electron should forget about the state of...

Hi - First timer here. Excuse me if this question is not up to the level i see posted on this forum, but here goes. I have been asked to provide a daily signal generated from the number of occurrences of a set of specified phrases present in a news data feed. The first thing I did is...

Statistics Problem :( An art collector, who owns 10 paintings by famous artists, is preparing her will. In how many different ways can she leave these paintings to her three heirs? Reasoning this out, she can leave 10 to the first heir & 0 to the others, 9 two the first heir & 1 to either...

I was recently accepted into a program at Western Michigan with this title. I was wondering if anyone here happened to have any personal experience, or knew someone who was in a program like this. Here's the program description. http://www.stat.wmich.edu/programs/grad/msstat.html My main...

This is my question: Find the Maximum Likelihood Estimator for f(y / x) = (x + 1)y^x, 0 < y < 1 and x > -1 OR 0, elsewhere. I think this is how you get started, but I get confused. I'm not sure how to continue. The likelihood function defined as the joint density of Y[SIZE="1"]1...

1. Let X1,X2, ... ,Xn be independent identically distributed random variables with ex- pected value \mu and variance \sigma^2: Consider the class of linear estimators of the form \mu\widehat{} = a1X1 + a2X2 + ... + anXn (1) for the parameter \mu, where a1, a2, ... an are arbitrary constants. a)...

Hi, I'm in need of a book recommendation :smile: . As a practicing physicist I get to use some statistics now and then. I've been through all of the introductory probability courses and I can solve textbook problems (after scratching my head for a bit). The problem is, I've never really...

Hi all I took a course subject in basic statistics but its been so long ago I find that I have mixed up or forgotten some of the concepts so I hope someone here can help me refresh my memory. 1) Probability starts from 0 to 1, you can have any range of numbers but they cannot exceed 1 or...