Statistics Definition and 998 Threads

Originally, it is derived from the weight of a confuguration,i.e. how electrons are distributied in different energy level:n=gexp(a+be) It gives the number of electrons in each energy level.However suddenly it can be apply to a cloud of gas?? By dividing a box of gas into different energy and...

Homework Statement Simple regression without a constant Yi = Bxi + epsi for i = 1,2,...n epsi are independent and N(0, sigma^2) distributed, B and sigma^2 are unknown. All my sums are from i = 1 to n The question is: Explain why: \frac{\hat{B} - B}{S} \sqrt{\sum{x_i^2}} is...

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...

1. The problem statement: A set of measurements of a parameter x has a normal distribution with mean of 50 and standard deviation of 1. If there are a very large number of measurements, approximately what percentage of measurements would you expect to be in the range 48 < x < 50...

Hello, I got a question regarding the probability amplitudes of polarization. Say you rotate the polarization amplitudes to 45% so the photons that pass through a filter have 50% probabilty of vertical or horizontal polarization. Is that 50% probabilty much like the probabilty of say...

Homework Statement Find the Z value that corresponds to the given area. http://img163.imageshack.us/img163/3785/problem1v.jpg The Attempt at a Solution What I did was go to Table E and find the closest number to 0.0166 which was 0.0160, and the Z numbers were 0.04 and 0.0. I then added them up...

Homework Statement Let X1, X2, ... Xn be n mutually independent random variables each of which is uniformly distributed on the integers from 1 to k. Let Y denote the minimum of the Xi's. Find the distribution of Y. Homework Equations The Attempt at a Solution I can see that P(Xi = j) = 1/K...

What are the odds that no one in my group has an October birthday? There are 43 people in the group.

Hey everyone, This is for someone who has used R. Please tell me how can we sum a function with a free parameter in R. I used the normal command f=function(n) sum(body of function containing n) it does not show any warnings till here, but when I plot this sum vs n (which i now define as a...

Hi guys, I'm having a hard time figuring out these two expectation problems below. Can someone please help me? For this problem, here's what I got: x...300...? p(x)...0.998...0.002 I can't seem to figure out what to put in the ? (loss). Maybe i just don't understand the wording of the...

Hi guys In my statistics book there is an example. They say that we see 3 occurrences of type A, and theoretically expect 7. This is a difference of 4, since we know that the standard deviation is 1.65 (they calculate it), then the difference is 2.4 standard deviations. Looking at a table of...

Hi, Well, I thought posting this question here is more relevant. I want to self-study a book about error analysis and data fitting. I have two books available, the one by bevington and robinson: "Data Reduction and Error Analysis for the Physical Sciences" and the one by taylor: "An...

R statistics program, is there a "and" statement I am trying to use R and need to use "and" as in if x is larger than y and smaller than z. I have tried to google and the manual, but I can't find it.

hey so i am trying to solve the following question but i have no idea how to solve it. I am confused by the %'sConsider a similar study done that shows that 96 % of those born in Canada can swim but only 83 % of new Canadians can swim. In a random group of 11 new Canadians, find the probability...

Homework Statement An analyst is presented with lists of four stocks and six bonds. He is asked to predict, in order, the two stocks that will yield the highest return over the next year and the two bonds that will have the highest return over the next year. Suppose that these predictions...

Homework Statement Suppose P(A) = .6, P(\overline{A} | B) = .4. Check whether events A and B are independent. Homework Equations Two events A and B are said to be independent if P(A|B) = P(A). This is equivalent to stating that P(A \cap B) = P(A)P(B) If A and B are any two events, then...

Hey, I am an undergrad planning on grad school for statistics next fall. I have the summer and next semester to take some courses. I would like to take some math that interests me but I also would like to do something that will be useful to graduate school. I have pretty much taken minimal...

I am using this book for a mathematical statistics class I am in. I have an account with cramster to check answers since they have solutions to nearly the entire text, but they are HORRIBLE. Half of the time they are dead wrong and they always lack decent explanation which is pretty key in...

What is the difference between applied and mathematical statistics ? Does applied statistics skip a great deal of necessary knowledge ? Is applied statistics enough to construct statistical models?

I'm learning modern physics and my book starts out with teaching distribution functions, but not to well. I need an intro that is not afraid to use an integral, but yet does not breeze through it as fast as this physics book. The book wants to know distribution functions to learn about plank's...

A certain number of persons (for example 100) choose the days of the week they prefer for a meeting, a fest, an event. The day preferred by most of the persons (for example 40) is Monday. If the meeting is every Monday, at the end of the year the number of persons who partecipated would be the...

Homework Statement Hi Say I have the following bin sizes, where the number in paranthesis is the amount of data points contained in the bin: 20-29 : (2) 30-39 : (7) 40-49 : (12) 50-59 : (14) How would I go about and find the mean for this binned data? I know that I should use...

Homework Statement The average salary for an employee at ABC Ltd is £30,000 per year, with a variance of £4,000,000. This year, the management plans to award every employee a fixed end-of-year bonus of £500 and an incentive bonus that is equal to 10% of the employee's salary. a) What is...

Homework Statement Mean of 25 and standard deviation of 5. Rescale the test using linear transformation so that the mean is 100? and the standard deviation is 20... Homework Equations xnew=a+bx The Attempt at a Solution I don't know...15+4x? I really don't understand how to...

What sort of a blend would this be? Let's say I am interested in being part of a research in some physics discipline but not necessarily as a physicist but as a statistician/data analyst. Like The guys/girls who compile, analyze etc the data from experiments on particle interaction, for example...

Hi, everyone: I am teaching an intro. stats course, and I want to find a convincing explanation of how we can "reasonably" estimate a population parameter by taking random samples. Given that the course is introductory, I cannot do a proof of the CLT. Specifically, what has seemed...

There are lots of books on statistics and probability that contain examples such as throwing a die or the number of buses passing through a particular junction. However these are not examples that students find interesting or tangible in any way. Are there any resources that introduces...

If Var(Y)=\sigma^2, then Var ( Y2 ) = ?

Homework Statement the weight of items produced by a production line is normally distributedwith a mean of 12 ounces and a standard deviation of 2 ounces. a. what is the probability that a randomly selected item will weight between 8 and 16 ounces? (DONE) b. what is the probability that a...

Homework Statement the weight of items produced by a production line is normally distributed with a mean of 12 ounces and a standard deviation of 2 ounces. Suppose that quality control requires the weight of items to be within 8 and 16 ounces. You select 7 items at random (each item is...

need help with this problem x~normal(mean= 12, stdev=2) item weight from 8 to 16 ounces i have a random sample of 7 items and need to find the probability that 3 of those items fulfill the weight each item is independent this is what i got at the moment z=(16-12)/(2) = 2 p(z<2)-p(z<-2)...

Hi all, I'm wondering how to gauge the chances i have of making it into a PhD program. First approximation: took ratio of accepted students to number of students who applied. But: that produced a 116/487 = 24% chance of being admitted to U-Cal San Diego, verses a 45/260 = 18% chance of...

Statistics. The bane of my existence... and then a bit of statistics "revision" rears its (in my opinion) ugly head in my quantum physics course and I have absolutely no idea what to do. Homework Statement 1. Suppose you measure the height of all students at the University. You use a ruler...

http://prola.aps.org/abstract/PR/v58/i8/p716_1 I'm trying to read this, and it's not going very well! :frown: On the second page: What two numbers is Pauli talking about? Isn't a spinor of a particle usually characterized by a one number?

Hi there, I am thinking if statistics can tell us if a slot machine is fair or not? We know that there are so many outcomes of a slot machine and seems it is not practical to sample all possible outcomes to check if it is fair or not. So how does statistics work in this issue?

I mentioned in a thread on here almost a year ago now that I was considering making a change into math, after entertaining several other options and figuring out that I really enjoy math, and especially probabilty, I have decided to to move toward getting either another bachelor or a masters in...

How are IGE antibodies related to an increase of allergies in the world?

The average amount of time people spend on facebook each day is 64 minutes, with a standard deviation of 4.5 minutes. Are you more likely to select a random person that spends less than 62 minutes per day, or a group of 35 people that spend on average less than 62 minutes per day on facebook...

Hi all, Just looking for some opinions on how to approach reporting the variability in some data I have acquired. I know Rutherford is quoted as saying “if your experiment needs statistics, you ought to have done a better experiment”, but unfortunately in biophysics we’re always at the mercy...

Hi all, I've search for my question and found no answer. I think it should be pretty simple... Fermi energy corresponds to the last occupied energy, as I understand it. So, energy levels in the Fermi gas are all filled with two electron of opposite spins, up to the Fermi energy. Saying it...

Homework Statement Three cards are dealt from a well-shuffled deck. (a) Find the chance that all of the cards are diamonds. (b) Find the chance that none of the cards are diamonds. (b) Find the chance that the cards are not all diamonds. Homework Equations Not sure ... The...

Hi, I am curious about how to describe the stability of a graph using some form of bona fide statistical analysis. I unfortunately have very little statistical background. The data come from a Computer Science research project I am working on. We are attempting to use simulated...

Hey I am transfering to the University of Florida next semester. Which one of these classes is easier? Business Statistics or Calc 1 w/ analytical geometry? I want to go higher up in Math and I was thinking calc 1 w/ analytical might help me before I take Business Statistics? Right now I am...

Which one do think is better for physical science?...one which help the most!

Hi. I am going to have my Multivariate Statistics exam in two weeks. I am going by a book that isn't available in the English literature. But I don't like it, because it has several omissions. Can you recommend me any good books in English? I can borrow many (for free) at my institution's...

Hi all, I was wondering if there was a way to see 1) average Physics GRE score 2) average GPA 3) average # of publications 4) etc.? of admitted grad students for a given PhD program. It seems to be of no use contacting the individual departments to see if my application is strong enough to...

Homework Statement The Attempt at a Solution The textbook says the answer is 0. I think they get that by saying that 5% of 240 is 12. So the plane is overbooked by 12. So there are 252 people booked on the plane. Then the binomial expectation is (252*0.95)=239.4. Which means they payout...

Homework Statement I need help solving this problem: Let A, B, C, D, and E are 6 units of a population. The measurements associated with A, B, C. D, E units are 76, 77, 78, 81, and 82, respectively. -Find the population mean and its standard deviation -List all possible samples of size 3...

Homework Statement The entering class in an engineering college has 34% who intend to major in mechanical engineering, 33% who indicate an interest in taking advanced math as part of their major field of study, and 28% who intend to major in electrical engineering, while 23% have other...

Hello, Suppose we have the following set of independent and identically distributed exponential random variables: \gamma_1,\,\gamma_2,\ldots ,\,\gamma_N. If we arrange them in ascending order we get the following order statistics: \gamma^{(1)}\leq\gamma^{(2)}\leq\cdots\leq\gamma^{(N)}. I...