Standard Definition and 1000 Threads

What is the significance of the standard deviation (equal to the mean) in an exponential distribution? For example, as compared to the standard deviation in the normal distribution, which conforms to the '68-95-99.7' rule? thanks

Homework Statement Vapour pressures of a liquid have been measured and fit to the following equation: Log10 P (mmHg) = -3571/T + 8.999 The melting point has been determined to be 392.7 K. A Cp value given for the liquid is 250 J/mol K and the ΔSvap is 117.20 J/mol K Homework Equations...

Homework Statement vapour pressures of a liquid have been measured and fit to the following equation: Log10 (mmHg) = -3571/T + 6.124 The melting point has been determined to be 392.7 K. A Cp value given for the liquid is 250 J/mol K and theΔSvap is 117 J/mol K Homework Equations...

Homework Statement The vapour pressures of a liquid have been measured and fit to the following equation: Log10 (mmHg) = -3571/T + 6.124 The melting point has been determined to be 392.7 K. Calculate the standard entropy of the liquid at the melting point. Homework Equations...

There are quite subtle gauge anomaly cancellations in the standard model. Does anybody know a good summary about the algebraic constraints for number of fermions per generation, value of electroweak charges, etc.?

Hello I am working on deriving the expression relating the equilibrium constant K to the change in Gibbs energy. This part seems to be followed okay, but here I am not following why the change in Gibbs energy of reaction is defined this way. I can see why K is defined in a way because...

Hello! I'm working on creating a sci-fi setting for a tactical space combat video game and short story series, and I had a few questions I couldn't find much info on after googling. I'll be playing a little bit loosely with the laws of physics for the sake of gameplay and storytelling, but I...

this is thing I'm thinking about for few years. why standard passenger car diesel engines are so limited in engine capacities range? if we take petrol engines, there are anything from 1.0 liter to 3.0l Inline 4 cylinders, 2.0-4.0l 6 cylinders (or even bigger in USA), 4-7l V8 etc. but take...

In my previous two math classes I'd get the answer wrong if I put the number first then the variable as my answer. Now in this class this way of doing it is wrong. I'm seriously confused now. For instance the last two classes said that it was standard practice to write an answer like: 3x+4. This...

If thermodynamic temperature can be interpreted as the average kinetic energy in a system, is there a quantity defined as the standard deviation? For example, let's say you poured some hot water into a cup of cold water. The instant you poured it the standard deviation of the system would be...

In the Gibbs free energy equation, does the standard change in entropy equal q(sys)/T(system)? Or in math terms: T(surr) * q(sys)/T(sys) = T(surr) * dS(standard) Thus dS(standard) = q(sys)/T(sys) (surr) = surroundings (sys) = systems (standard) = at standard conditions

We're doing electrochemistry this week and this concept confuses greatly. I know that voltage is the work per unit charge. And electrons move from high potential(is this voltage as well?) to low potential- what is meant by this by the way? How is this related to standard reduction potential? If...

Homework Statement Here is a slide in my notes: I am kind of confused about mean and standard deviation. So in my notes it says X1 to Xn are independent measurements. Then it says each independent measurement has a mean μ. But how is this possible, if they are independent measurements (in...

good day everyone, I wonder if anyone can direct me please on the international standard number or name that explain the safety and standard procedures in better distribution of power in breakers and panels from transformers. in short, as I learned in my school and as best practice that...

In some textbooks ##\Delta \hat{x}## is called dispersion of coordinate ##\Delta \hat{x}=(\langle \hat{x^2} \rangle-\langle \hat{x} \rangle ^2)^{\frac{1}{2}}##. For me that is standard deviation. What do you think?

How to transform a random variable CDF to a standard normal Given F(x) = 1- exp (-sqrt x), for x greater that 0 Thanks.

There are several ways to show the one-to-one correspondence between P(N) (= the power set of the natural numbers) and the set of the reals (or, equivalently, the set of reals in the interval [0,1).) Continued fractions, and all that. However, one argument is the following (sorry, this argument...

Hello A manufacturer produces blocks of metal of length 100 standard deviation 2, width 200 standard deviation 1 depth 150 standard deviation 3 The mean volume will be 100x200x150 but what will its sd function be? (The figures I've given are just for clarity) Thanks in advance...

Does anyone know what [SIZE="4"]L is? I'm trying to see if I could find videos on it on YouTube. On the first question this is what I think- [a;b] is a vector by the way: 1) [2;1]c1+[7;4]c2=[1;0] [2;1]c1+[7;4]c2=[0;1] I could have also combined those two by having the linear combination equal...

Homework Statement I have a set of values from a laboratory work (standard Additions practical), which I am required to plot. I am finding difficulties in plotting the values in excel because the horizontal axis must have some negative integers. Homework Equations The Attempt at a...

Homework Statement For a certain random variable X, P(X≤500)=.5 and P(X>650)=.0227, find σ. Homework Equations μ=expected value=mean Variance=∫(X-μ)2fx(X)dx evaluated from -∞ to ∞ σ=√Variance The Attempt at a Solution I'm not sure what the relationships between the...

Homework Statement Let X1,X2,X3 be a random sample from a normal distribution with mean μ≠0 and variance σ2=1/24. What are the values of a and b, respectively, in order for L=aX1+4X2+bX3 to have standard normal distribution?Homework Equations σ=1/√24 Converting normal distribution to...

I have an application where I need to find the density of a substance at standard conditions (101.325kPA, 15°C) from the density at recorded conditions (varies). The first application is for natural gas at approximately 11Barg (160 psi, 1100kPA), 80°C (176°F). The second application is for...

What is a Standard State or Reference State of an element? Can someone please give me a simple explanation of what a standard state or reference state is? I don't quite understand the way wiki describes it which is - The standard state, also known as reference state, of an element is...

In the standard model, the Lagrangian contains scalar and spinor and vector fields. But when we consider spontaneous symmetry breaking, we only account for the terms contain only scalar fields, " the scalar potential", in the Lagrangian. And if the scalar fields have vacuum expectation value...

Could you have a hypothetical universe with only photons, electrons, and positrons by adjusting the parameters of the Standard Model to eliminate all the "other" stuff? If so is String Theory flexible enough to model a hypothetical universe with only photons, electrons, positrons, and...

Hello, I am confused about the following scenario. Suppose I have the reaction CO (g) + 2H2 (g) → CH3OH (g) and I am asked to solve for the heat of reaction at 800 C. My query is the following: when finding the heat of reaction at standard state, which heat of formation I should use...

This paper, http://arxiv.org/abs/1402.2717, discusses an alternative model for SN1a progenitors and offers observational predictions to test it based on SN2014J. If the model is validated it would have far reaching consequences for cosmology.

After filling out the table, I used it to finally calculate the standard deviation as 0.105. Just to make sure, I ran it through Microsoft Excel and got 0.942809042. I put two together and figured I'm doing something wrong after the xw column because Excel agrees that the mean is also 1.7...

Hi; I've been trying to solve the problem myself but i really don't what could be wrong; The problem says : Make the change of variables x=ucos−vsin y=usin+vcos where the angle 0<(phi)<2 is chosen in order to eliminate the cross product term in x^2+xy+y^2=6 Then find the standard form of...

I am a programmer and physics fan. A speaker (Lawrence Krauss?) at https://origins.asu.edu/events/great-debate-parallel-realities-probing-fundamental-physics (not on youtube yet) said physics theories beyond the standard model are an under-determined problem. There are 7,000 theories that fit...

Hello, PF! [My question pertains to a non-rigorous, undergraduate introductory Probability and Statistics course. I'm no math major, so please correct me if I've mishandled any terms or concepts as I try to express myself. I'm always eager to learn!] * * * In a discussion of the...

I am a MSc student and I am looking for a place to do my PhD in Physics Beyond the Standard Model (Theoretical side). Any suggestions for a place to apply?. I know that there are the traditional elite places like MIT, Standford, Berkeley and so on but I am looking for other suggestions given...

Homework Statement Graphite can be change into diamond according to the following equation: Cgraphite ==> Cdiamond Consider the following reaction equations: Cgraphite + O2 (g) ==> CO2 (g) ΔH = -393.5 kJ/mol Cdiamond + O2 (g) ==> CO2 (g) ΔH = -393.4 kJ/mol Which form of...

I am wondering whether discussions of inflationary cosmology in these forums generally includes or explicitly excludes prior Plank era and GUT era dynamics. I never gave it any thought until reading the following. The Wikipedia article provides a perspective I just don't remember from other...

For a set with n points of data, why is the "degree of freedom" of the standard variance n-1? Hell, what does "degree of freedom" actually mean? Heck, my book "proves" this by saying that since ##\sum_1^n (x_i - \bar{x}) = 0## (obviously), then ##\sum_1^n (x_i - \bar{x})^2## must have n-1...

Hi all, Would a heading of 330 degrees be equivalent to a standard angle measurement of 30 degrees? I'm used to calculating by subtracting the heading from 90, but the angle is too large for this problem. I know it seems to be a ridiculously simple question compared to others on this forum...

Studying for my proofs final right now...there's a problem on the study guide: True or False. Assume standard properties of real numbers. Support your answers. (a) For all \(x\) in the real numbers, there exists a \(y\) in the real numbers such that \(x+y>0\). The answer: True. Given an \(x\)...

In Standard Hydrogen Electrode why only Platinum electrode should be used and why should it be dipped in HCl?why can't we use any other metal dipped in any other acid other than HCl?

Hi,,,can u please explain me how to calculate standard deviation and standard error for a binomial distribution when you have several samples? For exapmple: I don't know the population size. I take a sample of 10 and check for a particular characteristic. Let's say number of successes for this...

Hello all, I don't have a question on homework specifically, but I need clarification on something I'm reading in the textbook. I will be starting an abstract algebra class in the spring and it's been quite a few years since I've had linear algebra, so I'll be reviewing that material before the...

I have a question regarding symmetry groups. I've often heard that the Standard Model is a SU(3) x SU(2) x U(1) theory. From what I understand these groups contain the symmetries under which the Lagrangian function is invariant. If so, what does every one of the 3 groups above contain (what...

I had this problem on a quiz and obviously got it wrong, I am confused about how to set this question up and what to solve for: In a large city, the average retail price of a pound of grapes is $1.79, with a standard deviation of 18 cents. Between what values must be the price of at least 15/16...

In other words, can dark matter be reconciled with GR without drastically changing the idea that force is due to space-time curvature? and in the case of the standard model is there any thoughts of how the force of dark matter is transmitted via the exchange of a particle? It seems that this...

Hi guys, I hope someone is able to help me with this, I'm currently stuck on a problem. 1. I was given some data (in continuous, grouped form) regarding phone call times for a call center agent and asked to represent the data using the most accurate form of average. I initially calculated...

Hi guys, I hope someone is able to help, I'm currently stuck on a problem. I'm having trouble justifying which representation is more accurate for my data; either mean with standard deviation or median with IQR. I've calculated both averages for the my data, however I was advised by someone...

Homework Statement I have to calculate the standard deviation Homework Equations http://0.tqn.com/d/statistics/1/0/M/-/-/-/standarddev.GIF The Attempt at a Solution 0.64 0.4096 2.06 4.2436 0.16 0.0256 3.24 10.4976 1.74 3.0276 1.06 1.1236 4.04 16.3216 1.56 2.4336 1.3 1.69...

Problem: I need to use the Monte Carlo method to generate the mean, variance and kurtosis of the standard normal distribution. It has to be coded in Matlab, so there are two parts to this question: 1) The theory 2) The code Any help on either is appreciated. My attempt: To find $E[X]$ for a...

Homework Statement Suppose that we observe the redshifts and apparent fluxes of a sample of standard candles. When observed at a distance of 1 Mpc, the standard candles are known to have a flux F1Mpc = 1. From this sample of standard candles, we can measure the Hubble constant H0...

Hi everyone, :) I have a little trouble understanding what Canonical basis means in the following question. I thought that Canonical basis is just another word for the Standard basis. Hope you people could clarify the difference between these two in the given context. :) Question: Find the...