Statistics Definition and 998 Threads

Hi all, I have no experience with multivariate statistics but I'm trying to figure out a type of problem that seems like it should be easy, but I don't know where to begin. I ran into the problem in my research, and I don't have a strong statistics background. I'll try to explain it with an...

Homework Statement This was an example but I am not sure why there is a difference in the way they are calculating the standard deviation. A type of battery is produced with an average voltage of 60 with a standard deviation of 4 volts. A: If 9 batteries are selected at random, what...

Homework Statement so i was oping to prove the following are equivalent: \int_{-\infty}^{\infty}c^m B_x(c)dc=\lim_{n \to \infty}\frac{1}{n}\sum_{i=1}^{n}x_i^mHomework Equations \int_{-\infty}^{\infty}B_x(c)dc=1 x_i is a random variable. B_x(c) is a pdf The Attempt at a Solution i was going to...

Consider a monatomic gas of hydrogen (just to make the example as simple as possible) at a temperature T. If I use Boltzmann statistics, I would say that the probability of finding any arbitrary atom at energy E should be proportional to ##g_i e^{-E_i/(k_BT)} / Z(T)## where ##g_i## is the...

Hi, This is not really a homework question. Attached is a slide from a statistics presentation I found on the web. I am not sure what conclusion I can draw from this data if I ignore the outlier (1906). Saying "higher magnitude earthquakes result in fewer deaths" seems totally...

Basically what the title says, how is the job outlook for a BSc in statistics, is it worth pursuing a MS in it?

So I made an attempt to solve question 1, but I am stuck with question 2. I know that I need to use binominal distribution, but am unclear of the proper steps. Can anyone provide some help? 1. Suppose you want to show the significance of an effect size of 0.20 between your sample mean and a...

Homework Statement Through a sample, a party A wants to determine the percentage p of the voters, who voted for party A. They want to determine p with a 90% certainty to 5%. How many people do they need to survey? Let X be the amount of party-A-voters from n surveyed people. I don't need the...

So I made an attempt to solve question 1, but I am stuck with question 2. I know that I need to use binominal distribution, but am unclear of the proper steps. Can anyone provide some help? 1. Suppose you want to show the significance of an effect size of 0.20 between your sample mean and a...

Homework Statement Suppose a sample of size 10 is drawn from a distribution with probability density function ##f(x, \theta) = 2x^{\theta}(1-x)^{1-\theta}## if ##0<x<1## and ##0## otherwise, where ##\theta \in \{0,1\}##. Describe a best critical region of size ##\alpha## for testing ##H_0 ...

I'm planning to major in Applied Statistics, which requires me to choose a concentration in either Economics, Science, or Business. I know that Statistics is often applied to Biology (Biostatistics), but what abut Physics? Physics can often yield accuracy up to 100 percent, eliminating the need...

I need help with these statistics problems. Can anyone guide me through them? I would greatly appreciate it. I am completely lost on where to start. 1. Suppose you want to show the significance of an effect size of 0.20 between your sample mean and a hypothesized mean. You intend to conduct...

I have two questions: I have a set of data, a measured spectrum. When I model the spectrum with a function, I calculate r2=1-(\sum(y-ymodel)2/\sum(y-yavg)2). Q1) However, I have reference data now, which is what the spectrum should be. So is it right to use the same calculation on it for...

Hi, The question is: http://puu.sh/5GX2G.jpg http://puu.sh/5GX2G.jpg I am not exactly sure what the question is asking. Here is the answer/solution: http://puu.sh/5GX68.png But I am not sure what is going on. Could someone please explain what exactly the question is asking...

Homework Statement A Gallup Poll of 1002 adults in October 2002 found that 25% of the respondents said that their household had experienced a crime in the past year. Among respondents aged 18-29 years, 43% had been victims of a crime. Gallup says, “For results based on the total sample of...

Hello, I have a Bachelor of Science in Statistics from a Canadian University (York University). I've been trying to figure out what to do with my degree, but having problems figure it out. I was wondering if someone knows of some possible careers or jobs that require a degree a degree in...

Homework Statement Suppose you receive calls that follow a Poisson process model Y(t). There are two hypotheses, Hypothesis1: E[Y(t)] = λ1t = 71t and Hypothesis 2: E[Y(t)] = λ2t = 74t. Let t = 30 the number of calls be 2175. Find and compute a significance level α such that both...

I'm considering attending SF state to study Statistics with emphasis in Economics. However, I worry that the major isn't employable. If that is so, i would do engineering instead. How employable is a Statistics major? Do you think I should do engineering instead, even though I'm not that good...

Hello, I have some data that I am looking into correlation factors (Pearson). Let's say I have two data sets: X and Y. I have Graph X vs. Y then graph 1/X vs. Y. The reciprocal (1/X) yields a more linear relationship. Why does this occur? Thanks in advance!

So I've translated this assignment from another language, but hope it's good enough translated/understandable. Homework Statement According to the Statistics of Denmark, there was in the construction sector in the period 2009-2011 an average of 920 business bankruptcies per year out of a...

Is the wave function describing reality or does it describe the observers uncertainty about the system? I say that it's real but I would like to hear any comments or evidence that suggest the wave function isn't a description that has a one to one correspondence with a underlying reality. It's...

Just one short question about something I didn't understand in my book: "At low temperaturs only vibration modes where hω<kT will be excited to any appreciable extent. The excitation of these modes will be approimately classical each with an energy close to kT." I don't understand the last...

A probability problem (genetics), not homework, honest. 3 of 5 siblings are affected by an unknown inherited disease*. That this outcome is higher than 1 in 4 which is typically the case in recessive traits suggests that the disease is more likely to be dominant than recessive. Given 3...

Hi All, I am in the middle of my term and discovering that I'm terrible at Probability and Statistics. My professor is nice and so terribly clever that he makes it all seem reasonable (until I'm on my own with the text trying to make the work come out right.) If I don't change course, I 'm...

Suppose the force acting on a column that helps to support a building is a normally distributed random variable X with mean value 15.0 kips and standard deviation 1.25 kips. Compute the following probabilities by standardizing and then using Table A.3. a) P(X ≤ 15) b) P(X ≤ 17.5) c) P(X ≥...

Homework Statement Hey all, been having some problem with the rule..technique looks right but doesn't agree with wolfram's calc answer. Doing a moment generating function problem. M(t)=(e^5t-e^4t)/t, Find EX and VARX Homework Equations M'(0)=e(x) and so on.. The Attempt at a...

Hi there, Having done a Google, I wasn't able to find much information relating specifically to Poisson statistics and photon detections. I was wondering why photon detection experiments are calculated using Poisson statistics? (So for example, would Poisson distribution calculations be...

Hi PF, looking for a recommendation on a mathematically rigorous text on statistics (and perhaps probability). I have a decent amount of knowledge on linear & abstract algebra and calculus and analysis, so I don't mind if it uses them. What I don't want is a text that fails to prove its theorems...

Statistics problem---exponential approximation Homework Statement A box contains 2n balls of n different colors, with 2 of each color. Balls are picked at random from the box with replacement until two balls of the same color have appeared. Let X be the number of draws made. a) Find a...

Hey guys, I have this homework to do, but I can't find a solution. I need to solve this integral. It's Maxwell-Boltzmann Statistics, we are studying it in class of electronics. So, integral goes like this: ∫from Ws to ∞ [(W-Ws)(1/2)*e(WF-W)/kT]dW I have looked it up on google, but I...

Let number of energy levels be e(subscribe 0), e(subscribe 1)...e(subscribe r) N be the total number of particles and n(subscribe i) be the number of particle in with energy level where i =0,1,2,...r Let Ω be the number of ways attaining a given microstate Ω=N!/[ n(subscribe 0)!*n(subscribe...

The investigators suspect that military men may not tell the truth about visiting a CSW. Some may say they did visit a CSW when they actually did not; others will say they did not visit a CSW when they actually did. Is this: A. Nondifferential misclassification of exposure B. Nondifferential...

I've never really taken any statistics beyond a college introductory course, and I've been put off taking more because of the lack of mathematical explanations and clarity of the texts that are typically used. Since I have a decent math background (basic analysis, basic algebra) I would much...

A hospital complied the following annual statistic for 2009 (non-leap year) (I am not coming up with any answer below) January 1st-June 30th Inpatient service days 26510 Bed Count 160 July 1st-Dec 31st Inpatient service days 33910 Bed count 200 Dec 31 only Inpatient Service days 185...

I need help setting this problem up. 6 out of 10 patients discharged in 3 days or less, 12,000 admissions, determine how many were hospitalized over 3 days. Thanks for the help.

Recently, I came upon the Monty Hall Problem, and found it to be quite interesting. Any suggestions of similar counter-intuitive statistics puzzles would be much appreciated.

Homework Statement 3 randomly selected observations form the standard normal distribution are selected. What is the probability that their sum is less than 2? Homework Equations The Attempt at a Solution I know that the answer is 0.874928, but I don't know how to get that...

Homework Statement Anand, Bhadkamkar, and Moghe (1995) used a fractional factorial design to determine which of the six possible factors influenced the determination of manganese in cast iron. The six factors and their levels follow: A-Titration speed ; Medium...

I'm a bit confused about a particular step in a calculation. Given Theta_n = (2/n)(X1 + X2 + ... + Xn) being an unbiased estimator of Theta for a U(0,Theta), we have to prove it by showing E(Theta_n) = Theta. And we go on E(Theta_n) = (2/n)E(X1+X2 + .. Xn) Now at this point the solution is...

Hi guys, My friend was asked the following question in an interview: There are 3 weight scales and a 10kg weight. You weigh the 10kg on each scale 5 times (total of 15 measurements for the 3 scales), each measurement is a bit off the 10kg mark (lets say the first scale shows: 11kg, 9.4kg...

Crap. I couldn't get everything i wanted in my topic title. Anywho, I'm wondering which masters degree would be better for a career in machine learning / smart data while still keeping other - traditional options available? I would love to do a double major and earn both graduate degrees but...

This question is regarding the boson statistics and it’s relation to the uncertainty principle. Consider we have a vacuum state and we apply a field operator on it to create a particle at position x, we end up with state like \begin{array}{l} \left| \psi \right\rangle = {\psi ^\dag...

Does anyone have links to statistics detailing the plans of most recent American college graduates? For instance, about what % of 2012 graduates are going into graduate school? What percent of graduates are becoming full-time employees? What % are becoming waitresses, car mechanics, restaurant...

Homework Statement The moment generating function (m.g.f.) of a random variable X is defined as the Expected value of etX: M(t) = E(etX). The series expansion of etX is: etX = 1 + tX + (t2X2)/(2!) + (t3X3)/(3!) + ... Hence, M(t) = E(etx) = 1 + tμ1' + (t2μ2')/2! + (t3μ3')/3! +...

Hi Please advice me a good book on mathematical statistics.I want it to be oriented in math students or engineering level. Best Regards

Thermodynamics states that a system cannot become more complex without some sort of input (which would make it an open system). In other words, a closed system cannot increase in complexity. I understand that complexity is a very ill-defined term. However, at least in principal, couldn't a...

Good afternoon, I've come here to hopefully resolve an issue that cropped up in a debate with a friend. We were discussing weather patterns and chaos theory was brought up. My understanding of chaos theory is that it is a way of explaining behavior of certain deterministic systems aka...

Hi, Homework Statement n different balls are distributed independently between m boxes with unlimited capacity each. I am asked to find the expectation and variance of the number of empty boxes. Homework Equations The Attempt at a Solution The probability of i-th box being empty...

Homework Statement On p. 13, they present and discuss Table 1, summary scores for the test periods. At the bottom of the first column, they say that the "fall CBM WIF is 0.85 standard deviations below the mean." What mean are they referring to? What is the value of the mean? Homework...

Hi, Homework Statement I am having difficulties understand parts of the solution to the following problem in Statistics: Let X and Y be two random, continuous variables, where X is distributed U(0,1) and Y|X=x is distributed U(x,x+1). I am asked to find the marginal density of Y. Homework...