Statistics Definition and 998 Threads

1. Assume that there is a 50% chance of hard drive damage if a power line to which a computer is connected is hit during an electrical storm. There is a 5% chance that an electrical storm will occur on any given summer day in a given area. If there is a 0.1% chance that the line will be hit...

Hello! I have a small question, and I am not sure if I am missing something: Today I glanced at the wikipedia page for Pions, and saw this: Statistics: Bosonic Can anyone explain to me why a quark paired with a anti-quark obey Bose-Einstein Statistics? If quarks obey Fermi-Dirac statistics...

Hello, I've got some data on an epidemic in various locations - the total number of agents and number killed by the infection after 1 year. -This gives gives me a distribution of percentages of the populations that have been killed by the infection. (but all the percentage values are relatively...

This is difficult for me to describe. If anyone can get the gist of what I am talking about and can point me to the correct keyword, would be really helpful. I'll explain this through an example: I have many perfumes. I get surveys from people to see which perfumes they like more. The way...

This is NOT homework. This is a personal project I am working on. First and foremost, THANK YOU in advance for helping me with my statistics project that I have been unable to solve on my own or through the help of my statistics book and google. I am working on an excel spreadsheet for use...

What are some good texts for self-studying probability & statistics?

What does the term 'absolutely fair' in statistics & probability mean? Does it mean that the probability for each variable* is 0. And that the expected value is 0. I did a search on Google and the only thing I came up with was this: http://mathworld.wolfram.com/AbsolutelyFair.html

Any comments would be appreciated. Patent/Copyright Pending. :approve: Thanks ********************************SOP Follows************************** Statistics’ use in predicting and modeling are the most attractive to me. The ability to model phenomenon and...

Homework Statement Let X= \begin{bmatrix} X_1 \\X_2 \end{bmatrix} be bivariate normal N(\begin{pmatrix} \theta \\ \theta \end{pmatrix}, \begin{pmatrix} 1 & u \\ u & \sigma^2 \end{pmatrix}). Let T=aX_1 + (1-a)X_2. a) Write u in terms of \rho = the correlation coefficient, and \sigma b)...

Homework Statement Roll a pair of six-sided dice. If the sum is 7 or 11, you win. If the sum is 2,3, or 12, you lose. If the sum is any other number, you roll again. In fact, you continue throwing the dice until you either roll that number again (win!) or roll a 7 (lose!). Suppose you...

Let X be \Gamma(3.5,2). Find E(X^3). We can't write E(X^3)=E(X)E(X)E(X), right? (since they are not independent)... So I just tried to compute: E(X^3) = int_0^{/infty} \frac{x^3}{\Gamma(3.5)2^{3.5}} x^{3.5-1} e^{-x/\beta} dx But I'm having a problem, since \Gamma(3.5) = (3.5)! and I don't...

Let \bar{X} be the mean of a random sample of size n from a distribution that is N(\mu,9). Find n such that P(\bar{X}-1 < \mu < \bar{X}+1)=.90, approximately. My answer: -Z^* < \frac{\bar{X}-\mu}{9/\sqrt(n)} < Z^* where -Z^* and Z^* are the critical values. So... For the confidence...

Hope this is the right forum for my question. I'm into statistics and quite often see assumptions involving set theory. I know some set theory but am having trouble understanding it for any application. I would like to narrow this gap, maybe because this type of mathematics seems most...

In this link: http://www.math.harvard.edu/~phorn/362/362assn3-solns.pdf I do not understand how they got the power function for number 5...can anybody explain it to me please? Thanks in advance

Homework Statement OK I am dealing with a Queue type problem that is M/M/2. I have already solved most of the problem but I can not figure out how to solve for ∏0, Lq, L, & W. The information I am given is: λ=11.98, μ=7 and s=2. Homework Equations The Attempt at a Solution I am...

this isn't really homework, but I was just wondering if someone could offer an intuitive reason as to why when random variables are transformed, we use absolute values of derivative of those functions, as opposed to the functions themselves?

Homework Statement Given two events, A and B, state why each of the following is not possible. Use formulas or equations to illustrate your answer. d. P(B) = 0.24 and P(B|A) = 0.32 Homework Equations P(A ∩ B) = P(A) * P(B|A) P(B|A)= (P(A ∩ B))/P(A) P(A|B)= (P(A ∩ B))/P(B) The...

Hey, how can I run a analyse with SPSS statistics software for this data? (I am not a stats guy at all, and not sure about using SPSS) Group 1 is "Gym A" Group 2 is "Gym B" And the values are just the weight loss numbers. All we are trying to do is compare Gym A (group 1) to Gym B...

I am reading Henk Tijms' "Understanding probability" and have become a bit confused. A man deposits $100,000 in a pension fund for 20 years with an average growth of 14%. Assuming a fixed rate of growth of 14%, the book tells me that the equation below, solved for x, will give me the amount...

Suppose X_1, X_2, ... , X_10 is a random sample on a random variable X which has a Poisson distribution with mean \theta. Say the realized value of the sample mean is 0.5, i.e., n \bar{x} = 5. Suppose we want to compute the confidence interval (\bar{\theta}, \underline{\theta}). Using the table...

I'm currently taking a intro to statistics class. It's a quarter class so it just started a week ago. I got a lot going on this semester so after taking the class I feel I'll only have a computational aspect for statistics. I won't know much about the theory because I know I won't have much time...

Homework Statement People in a given community who have a certain disease is 0.005. A test is available to diagnose the disease. If a person has the disease, the probability that the test will produce a positive signal is 0.98. If a person does not have the disease, the probability that the...

Homework Statement Find the probabilities that the value of a random variable will exceed 4 if it has a gamma distribution with (a) \alpha = 2 and \beta = 3 (b) \alpha = 3 and \beta = 4 [b]3. The Attempt at a Solution [/b} how would I even attempt this question?

I'm looking for a statistical glossary - an organized and detailed list of concepts which constitute the field of statistics. I've already checked the glossaries of some statistics books; however, many of the said glossaries seem to use very general terms to define each glossary terms - they...

Hi there, This is going to be difficult for me to explain, so I will try my best. My statistics is kind of rusty... I've been given census data to analyze and I'm having problems. The totals are all given by the government. For a specific attribute I've been given rows of different areas...

I was just wondering how exactly to appropriately modify the 1st and 2nd order stats when you want to weight a given sample more heavily. If \vec{X} is my vector of N samples and I have a weight vector \vec{W} of the same dimension, which ideally is measuring the reliability of each sample...

Homework Statement The proportion of people in a given community who have a certain disease is 0.005. A test is available to diagnose the disease. If a person has the disease, the probability that the test will produce a positive signal is 0.98. If a person does not have the disease, the...

Homework Statement A certain delivery service offers both express and standard delivery. Eighty-five percent of parcels are sent by standard delivery and 15% are sent by express. Of those sent standard, 80% arrive the next day, and of those sent express, 95% arrive the next day. A record of...

Homework Statement I am just trying to figure out how to calculate the expectation of something. The context is for a random sample from a normal distribution with known mean μ and unknown variance σ2. Homework Equations 3. The solution So for the purposes of this question we set θ = σ2 I...

How bad is my statistics knowledge based on the following mind map? Any concepts which aren't bold are the concepts that I know; the bold ones are the ones I'm currently learning. The mind map in question: http://i.imgur.com/4He3f.png What should I learn next based on my current...

I need some good online resources for learning statistics. Can I opt for video tutors, suggestions please...

Homework Statement Homework Equations The Attempt at a Solution Here's what I've tried so far, not really sure how to go on with these problems. Been reading the textbook up and down on Poisson processes! Any hints or help? Especially 1.B, 1.C and 2.B, 2.C

Let's say that a treatment A has been proven to have an impact on the levels of B with a given confidence interval. Let's also say that we know that the treatment C causes the treatment A to be imposed on our sample. Before the testing on the effects of C has been done, which statistical models...

Hey guys, I'm stuck on a question in my homework assignment and I was wondering if you could push me in the right direction? So here's the question: X and Y are continuous random variables with joint pdf f(x,y)= 4xy (0<x<1, 0<y<1, and otherwise 0). Find the pdf of T=X+Y using the CDF...

Applied math vs. statistics PhD -- job prospects I'm a math major considering pursuit of a PhD in applied math or stats when I graduate. I'm trying to ascertain the job prospects in these fields. Can anyone provide some information on how readily jobs are available in industry and academia in...

Does anyone here know any good Bayesian statistics, Bayesian hypothesis testing, Bayesian inference, etc. learning materials (preferably online)?

Homework Statement 1) S'pose we flip 2 fair coins, and roll one fair 6 sided die. What is the probability that the number of heads equals the number showing on the die? 2) We roll 4 fair six sided dice. What is the conditional prob. that the first die shows 2, conditional on the event that at...

Homework Statement For any cdf F(x) of a continuous random variable, show that \int_{-\infty}^{\infty}[F(x+b)-F(x+a)]dx=b-a for any a<b. Homework Equations The Attempt at a Solution Not really sure where to begin. I figure I can split the integrals and do u subs, and (after...

Homework Statement There is a city with 10 million people and an average human has 110 000 hairs. Prove that there is at least 2 people with the same amount of hair. The Attempt at a Solution I really have no idea of how to even start solving this problem. Sorry. Also, sorry for the...

Which branch of statistics and mathematics deals with extrapolations and trend analysis? That is, where one can estimate various trends (be they exponential, linear, etc.) that apply to our data and draw a trend which could extrapolate the future variation. Am I referring to the time series...

Homework Statement I am not sure whether the answer should be b or d. It says the average of the function and the vertical scale need to be determined. In other words I won't have to determine a_0 (the vertical shift) right? Because it did not mention that? Also what is the average...

Homework Statement This problem is taken from the 2011 AP Statistics Exam, which we reviewed in class. The exact problem can be found here, and solution after: http://apcentral.collegeboard.com/apc/public/repository/ap11_frq_statistics.pdf...

Homework Statement Professor E.Z.Stuff has decided that the least squares estimator is too much trouble. Noting that two points determine a line, Dr. Stuff chooses two points from a sample of size N and draws a line between them, calling the slope of this line the E.Z. estimator of beta1 in...

It is said that is there already n bosons in a particular quantum state, the probability of another boson joining them is (n+1) times larger than it would have been otherwise. But if we apply this rule to calculate probability for one horizontally (H) polarized photon to join a bunch of n=99...

Hi Everyone, I am trying to rank football coaches and I'm a little confused on how to choose the weights to put in each variable. So far the variables I have decided to use are: total career wins, total winning percentage, current season winning percentage, current season total point...

Homework Statement Problem 2 Assume that the number Y of customers entering a store is a Poisson random variable with rate λ . Let X denote the number of these customers being a woman. The probability that a customer is a woman is denoted by p. Also, assume that all customers enter the...

I'm taking microfabrication right now and we will be making a flow cytometer on a chip. My question is--are the statistics that come from something microfabricated as good as the larger version? The idea is to use less reagents, materials, and sample, but if you use less sample can you...

Homework Statement The following data were obtained for trace elemental zinc in a particular sample of high purity (%Au> 99.99%). The results are given in mg Zn/ kg Au. 15.38, 15.17, 15.33, 14.88, 14.71, 15.42, 15.60, 15.22 Find the zinc content and the uncertainty at 95% confidence...

Homework Statement This is actually not a homework problem, but as it is very basic material, I post it here. I have two variables each with its marginal probability (estimated from data). I also have the correlation (variable). Homework Equations How to find the joint/conditional...

I've been taking this course for 2 weeks now. I have no clue what is expected to be known from a course like this. I will be speaking with my professor after the next lecture. Can anybody who has taken this course give me some tips to understanding what I'm supposed to be getting out of this...