Mean Definition and 1000 Threads

Hello This is a really silly question but I have doubted myself and I was wondering if anyone could help. I have been given the following information:-I am trying to understand what it means when the title states Unit Weights? I thought these were density but density is kg/m^3 - whereas these...

I am getting a complex number for my transmission angle in part (c) but I do not know what that means. Am I even doing this correctly? Any help will be greatly appreciated. Thanks!

Sorry, I am not sure where to post this But I used Webster's dictionary and the free dictionary online to look it up and both dictionary's had 2 main different definitions for what a hypothesis means. The free dictionary states: 1. A tentative explanation for an observation, phenomenon...

hi. How to obtain the expected value of x in the momentum space ?

Hello everybody, In all QFT courses one starts very early with commutation and anti-commutation relation. My main question is why do we do this and what is the motivation? I have already asked few people including our professor but could not get a clear answer. I am talking about the...

Hello! I have an experiment and for some reasons I was able to do only 4 measurements and they all ended up having the same value, say for the purpose of this post ##100 \pm 1## where the error of 1 is estimated based on the measuring device resolution. The mean is obviously 100. Usually the...

THE PROBLEM 6) Table 1 below contains data on offensive statistics for each game in the 2019 UW Husky Baseball season. Answer the following questions and/or complete the specified tasks using these data. Do everything by hand and show your work (good practice for the tests). a. Construct a...

Summary: What did Omnès mean with this? I found an old article by Roland Omnès which analyzes the EPR paradox and offers a solution to it (https://www.sciencedirect.com/science/article/abs/pii/0375960189900182). At some point, the article says: "Some macroscopic systems do not satisfy the...

Quantum theory shows that every and all posibile states exist. As we get better at measuring our visible and detectable universe, it becomes ever clearer that we are missing so much. My question is: If infinity is infinite, then that must apply to scale, could you have infinite multiverses in...

I investigate the damage to the metal surface with box-counting method and some surface images give a convex multifractal spectrum f for a result - which is also widespread in the literature, but some other surface images form a concave multifractal spectrum. Not much information is available on...

Are the interaction path and mean free path of a particle the same thing?

My question on neurons and memory.

Hello! I have some measurements with errors associated with them: ##x_i \pm \delta x_i## and I want to cite the value of the mean with its error. I see online that the error on the mean is defined as ##\sigma/\sqrt N##, where ##\sigma## is the standard deviation of my measurements and ##N## is...

What do we mean when we say that voltage drops across a resistor?and what does it mean when we say that a point is at lower potential as compared to some other point?Can we say that potential is potential energy per unit charge?

https://en.wikipedia.org/wiki/Size_effect_on_structural_strength#cite_note-1 I don't understand about non-random strength (f_t) and size effect of material And please explain to me for the size effect? :cry::cry::cry::cry::cry:

In a hypothetical, electrically neutral, ideal crystal, where all unit cells are identical, even the ones at the surface: What would the average value of the electrostatic potential be compared to that of the vacuum outside the crystal? Would it be the same or more positive? As a simple example...

Just as the title says, I am trying to figure out what they are actually telling us when they say something is so many light years away. If you were to search the internet "what is the most distant object ever observed" you will be told it is a galaxy 13.3 billion light years away. Do we...

Why when a capacitor is fully charged the circuit is acting like an open circuit? And what is the meaning of "fully charged", if the charge as a function of time equation is: $$ Q = CV_b [1 - e^{\frac{t}{RC}}] $$ so by this equation the charge on the capacitor will never reach exactly, Q = CV...

Hi I tried like this. ##σ^2=<(λ_1+λ_2+,,,+λ_i)^2>=<λ_1^2>+<λ_2^2>+,,,<λ_i^2>## And I know ##σ^2=Σ_in_iλ_i^2##from equation (4-12) (so this is cheat 😅). So I know also ##<λ_i^2>=n_iλ_i^2##, But why?? I know if I take ##λ=1 ,σ^2=n##,But I don't understand ##λ≠1## version. Sorry my bad...

I am curently working on Forecast in cosmology and I didn't grasp very well different details. Forecast allows, wiht Fisher's formalism, to compute constraints on cosmological parameters. I have 2 issues of understanding : 1) Here below a table containing all errors estimated on these...

We have a periodic function ##f: \mathbb{R} \rightarrow \mathbb{R}## with period ##T, f(x+T)=f(x)## The statement is the following: $$\frac{1}{T}\int_0^T f(x)dx =0 \implies \frac{1}{T}\int_0^T\frac{d}{dx} f(x)dx =0$$ Can you give me a hint on how to prove/disprove it? The examples I tried all...

Hello guys, is it possible to "see" the mean value theorem when one is only thinking of numerical values without visualizing a graph? Perhaps through a real world problem?

What exactly is this equation telling me? How can I use it to work out the Equations of Motion given an equation of potential energy? Won't I have to solve a PDE? I'm extremely sorry if this question comes off ignorant.

I have a problem about Heisenberg model.When applying mean field approximation,why does the average of spin flip terms be zero(<S+>=<S-> = 0 )? Thanks

@davenn posted the following in the Lame jokes thread: Very funny, but I wonder how realistic this would be. What kind of anchoring could one use that would actually help in stopping the roof from blowing away?

What does observation means in Science. What is the definition? Is it like to do the two separate experiments, on the same topic and compare the results. Am I correct, Thanks In advance

Looked at some lottery wins and something was fishy. This a lottery where you pick 5 numbers out of the set (1,2, ..., 50). When no one wins, the money goes to the next iteration of the game so the prize gets bigger and bigger. It seemed that a win was too regular around every 2 or 3 weeks and...

Problem Statement Assumptions: a. The universe is finite. That is, it is (approximately) a 3D boundary of a 4D hyper-sphere of radius r. b. [The following is based on https://arxiv.org/pdf/1502.01589.pdf as discussed in the thread...

In analogy to classical mechanics, I thought a good definition to "What does "solving a quantum mechanics problem" mean?" was to give the propagator (aka the Green function, or the 2-point correlation function): In classical mechanics, solving a problem means to give the path of the particle...

Here, i have provided the description of the mean molecular weight from my course notes as well as my workings. I'm not sure about my values for X and Y. It states that X=1 if all of the hydrogen is ionised which i think the 1 represents 100% hydrogen but the core is also made up...

in Clausius formulation, what does the phrase "from cold to hot" means? I can understand it intuitively but in the language of the zero and first laws, we have not defined a temperature scale, only equivalence classes of systems that will be in equilibrium with each other (systems with the same...

How can an ODE be symmetric? How would you plot an ODE to show off this property? (i.e. what would be the axes?)

However I have an optimization problem (minimization problem), and the table (attached fill) represents a comparative study between the results of two methods, the first one performed better than the second one and to quantify the effectiveness of the first method we computed the gap which equal...

This is my understanding.

The second postulate says the speed of light is constant c independent of all inertial observers. Does it mean the speed of the wave front relative to the observer , that is, the relative speed between the wave front and the observer?

New Wonder material: Borophene https://www.technologyreview.com/s/613267/borophene-the-new-2d-material-taking-chemistry-by-storm/ Sorry @Borek

if ##\bar x =\frac{\int x dv}{\int dv}=0## Is necessarily ##\bar {x^2}=0##??

Say Temperature of a gas doubles, I do not understand how the average distance between particles (mean free path) is unaffected if they are traveling √2 times as fast in a fixed volume V. Root 2 as a factor of increase because T*2 --> KE*2 --> V*2 --> Vrms*√2 Is it because relative to one...

This paragraph taken from a book : What does it mean the typical wave lenght?

Homework Statement Assuming a Salpeter IMF with upper and lower mass limits of 0.1 and 20 M⊙ respectively, calculate: (i) the mass point at which half the mass formed in a stellar cluster lies in more massive systems and half in less massive systems. ii) the mass point at which half the...

Hello Physics Forums, I have a simple parametric surface in R3 <x,y,z(x,y)>. I've calculated the the usual mean curvature: H= ((1+hx^2)hyy-2hxhyhxy+(1+hy^2)hxx)/(1+hx^2+hy^2)^3/2 I needed to take the variational derivative of this expression. Since it has second order spatial derivatives the...

Homework Statement I have a value of $$ U=U_0+x (∂U/∂x)+y(∂U/∂y)+z (∂U/∂z)+1/2x^2(∂^2U/∂x^2)+1/2y^(2∂^2U/∂y^2)+...$$ We need to find the mean value of the U. So the answer is $$\overline{\rm U}\approx U_0+a^2/24(∇^2U)$$Homework Equations $$\overline{\rm U}=1/a^3 \int \int\int Udxdydz$$ The...

Hello, yes. I have a question pertaining to probability and statistics and it concerns finding a weighted mean which is shown through calculating a GPA. In this context it pertains to a review I'm doing and I can't figure out how I'm getting it wrong. I may be missing something rather little but...

by this quote "If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut." i wonder if "z" means "say nobody about your results until they are published" or "work and do not gab on empty"

Not sure if this is the right "forum section" but what does "±" mean when it comes to writing a lab report? I don't remember this back in high school but idk.

I'm calculating current through a resistor by measuring a single current pulse, integrating it and multiplying it with its frequency. This would correspond to calculating an arithmetic mean. I also tried calculating RMS of this waveform, using GNU Octave, and was a bit surprised by the...

<Moderator's note: Moved from a homework forum.> Mass (g) +/- 0.01 grams Drop height (centimeters) +/- 3.00 Shell 53.47 45 No crack 56.78 45 Cracked...

I have been reading some fairly mind bending stuff about the principle or least time (and those of least action) raising questions about causality and free will. Can anyone explain this to me? Is this total 'woo woo' psuedo science, or are these philosophical questions widely accepted? Thanks...

Homework Statement I have simulated Langevin equation (numerically in Matlab) for some specific conditions, so I have obtained the solution ##X(t)##. But now, with the solution I have obtained, I have to calculate ## <X(t)|x_0>, <X^2(t)|x_0>-(<X(t)|x_o>)^2 ## and the conditional correlation...