Mean Definition and 1000 Threads

We have a question where we're testing the hypothesis that a certain diet (call it diet A) causes weight loss. We get ##n_1## people who we put on diet A (treatment group) and another ##n_2## people who we keep on a normal diet (control group). We find that the mean weight loss in the treatment...

I thought that maybe it would be a good idea to do gaußian error propagation of the formular of the mean, this should give me the uncertainty of the average i calculate from the sample i have... And additionally consider the standard deviation Can someone maybe give me a detailed way to handle...

See my image for my attempt at solving this problem. My approach varies significantly from the solution I have for this problem and I wanted to get feedback on if what I did is correct of where I went wrong. thanks.

A conducts an experiment. I don't know how to describe this experiment, but let's say he measures the masses of ##3## things and computes their sum. He finds that the mean mass equals ##2## units of mass. He considers this to be special in some sort of way, something that demands an explanation...

I recently came across the concept of 'mean free path', and some similar concepts in thermodynamics (the depth of my understanding is very shallow though, which is why I'm here). This is very much a shower though, so: Suppose I have a box filled with some some metal ball bearings, which I...

Looking at stats today, In my working i have; Let ##H_0 = μ_1=μ_2## v/s ##H_1 = μ_1-μ_2≠ 0## then, ##\bar x = \dfrac{134+83+...+123}{12}=120## ##\bar y = \dfrac{70+118...+94}{7}=101## ##t=\dfrac{\bar x- \bar y}{S_p ⋅\sqrt {\dfrac{1}{n_1}+\dfrac{1}{n_2}}}## ##t=\dfrac{120-101}{21.21...

**Problem:** Find parametric equations for a simple closed curve of length 4π on the unit sphere which minimizes the mean spherical distance from the curve to the sphere; the solution must include proof of minimization. Can you solve this problem with arbitrary L > 2π instead of 4π? There...

So I was thinking about arithmetic, geometric and harmonic means when I had a thought. Let's say we have a curve y = x^2. We want to find the AM of the points on the curve between x=1 and x=2 i.e. y = 1 and y = 4. To make thing easier, we'll start with just the endpoints and keep adding...

We have a collection of 8 discrete data points. They are: 10, 20, 30, 20, 30, 40, 30, 40 In increasing order: 10, 20*2, 30*3, 40*2 The harmonic mean of this data series is 22.86 I read on Wikipedia that the harmonic mean is skewed towards the smaller values i.e. smaller values will affect the...

Is it a total energy of a vibrating molecule? So is it a sum of potential and kinetic energy? Or it is only a total energy of a vibrational motion of the molecule? Or is it only a potencial energy, when it is related to a dissociation curve? I am confused.

I can look at it as if a vibrational motion of the atoms was a simle harmonic motion. So I can consider one of the two atoms to be at rest and the second one to vibrate. Its deviation can be written as ##x(t)=r(t)-r_0##. When I know that the hydrogen molecule stops exiting when the range of...

I would like a table of Earth mean temperatures going back as far as available. Where can I find that?

Physics did not begin in London in 1686. It began 2 centuries later in 1874 in Kristiania. @fresh_42 Sorry for the blatant off-topic, please explain this text in your signature. Thanks!

Perhaps this is a stupid question but, if Lorentz symmetry and time translational symmetry are not global in an expanding universe, wouldn't that mean that is possible that other Hubble spheres outside our observable universe could have other symmetries or an absence of the Lorentz symmetry? I...

Hello. I was wondering if the experts here would like to comment on this news? Thus far I've been unable to find a link to any science paper. Thank you, Cerenkov.

Question : For uniformly accelerated motion ##a(t)=a_0\;\; \forall \text{times}\;t##, we can say that the average velocity for the entire motion ##\bar v = \frac{v_0+v}{2}##, where ##v(t)## is the final velocity at some time ##t## and ##v_0## is the initial velocity. How do we show that? Issue...

Hello everyone, I'm reading "Special Relativity For the Enthusiastic Beginner" (by David Morin) and so far I really like the book, but I have a little bit of a hiccup in understanding terminology regarding stated symmetries or the lack there of in reference to the Galilean transformation when...

A certain mechanical appliance or device is given a rating that says, a certain operation or a certain movement can be performed some specified thousand times. What does the rating really mean? Was that movement or operation performed until the piece failed? Does it mean some advanced test...

If the distance between the centres of two molecules is σ, then imagining a a cylinder with radius σ the number of molecules can be given by πσ²cn where c = average velocity. So mean free path can be given by λ = c/πσ²cn = 1/nπσ². But do I derive it from exp(-x/λ)?

function checkBoundaryCollision() { if (x - ballRadius <= 0 || x + ballRadius >= canvasWidth) { dx = -dx; } if (y - ballRadius <= 0 || y + ballRadius >= canvasHeight) { dy = -dy; } } Full code here:

I am reading a research paper that says weak chemisorption of silver with olefins basically means more effective olefin/paraffin separation. If silver weakly binds to olefins, wouldn't that make a lousy separator?

I came up with two different forms of the sample space S, but I am not sure if they mean the same thing or the first one could mean something different. H stands for heads showing up and T stands for tails showing up. $$ S = \{ \{i,j\}: i \in \{H,T\}, j \in \{H,T\} \} $$ $$ S = \{ (i,j) : i...

Hi Pfs My question is not technical. I found papers about recoupling theories about spin networks. i see what they are about but why this word "recoupling"? Was there before a decoupling and recoupling whar?

Hi, I'm having trouble understanding that for time-like events where the order of time is absolute, these events can be in different spatial orders depending on reference frame. Can someone provide an example please? Thank you!

TL;DR Summary: So I'm just confused when the question asks me to solve for the no load speed of DC motors and induction motors. Does no load condition mean that the output torque (Tout) is zero? This is what I was assuming so far for both DC and induction motor. Is no load condition the same...

Given are a fixed point ##P## and a fixed circle ##c## with the radius ##r##. Point ##P## can be anywhere inside or outside the circle. I now draw two arbitrary lines ##l_1## and ##l_2## through the point ##P## in such a way, that both lines intersect with the circle ##c## in two distinct...

TL;DR Summary: So I'm doing this coding assignment that involves a simple processor with an ALU. I have a list of operation of the ALU but I don't understand one operation called BNEQZ. I have the list of operation below and an example of it being used to form some loop. Would be very grateful...

Can someone explain the question so I can attempt a solution? What does it mean by input and output and why is that relevant?

I don't understand why the identity is mentioned in the group's definition and how I am supposed to incorporate it into the table. I honestly have missed some lectures on Linear Algebra, and I can't find any examples or definitions for this in the prof's notes. I'd appreciate some help for sure...

A basic question. Looking at the NIST spectroscopic data, what exactly is, for example, Ar I vs Ar II vs Ar III? If Ar I is unionised Argon, then is Ar II an Ar- ion or an Ar+ ion? (and whichever way around it works, how do we denote the opposite ionisation? If they are all ionized, is there...

My book writes " The geometric distinction between timelike and spacelike distances is mirrored in the devices used to measure them. A clock is a device that measures timelike distances; a ruler is a device for measuring spacelike ones. Two nearby points or a timelike world line are timelike...

Hi Pfs Rovelli writes this in his book (Qunatum Gravity) about spin networks: Given an oriented and ordered graph there is a finite disgrete group of maps that change its order or orientation and that can be obtained as a diffeomorphism. A link is equipped the source and target functions. this...

I am refreshing on this... I think there is a mistake on the circled part in red...right? not correct symbol for sample mean...This is the part that i need clarity on. The other steps to solution are pretty easy to follow...as long as one knows the t-formula and also the knowledge to...

In Newtonian mechanics, G is simply a proportionality constant or the force with which two bodies of unit mass attract each other. However, GR doesn't treat gravity as a force. So how is G defined in GR? Is it a property of spacetime or just some useless mathematical artefact? What does G...

Hi, last semester I "solved" a full differential equation and the answer was (see the picture). What does it mean? Can I make a graphic with it or what? I really don't get it. *Arrows are just a continuation of the main formula*

The measurement for astigmatism is diopter. But what does 1 diopter of astigmatism mean? Thanks a lot if you help me figure this out!

Nuclear Fusion Breakthrough Confirmed: California Team Achieved Ignition BY JESS THOMSON ON 8/12/22 AT 9:20 AM EDT https://www.newsweek.com/nuclear-fusion-energy-milestone-ignition-confirmed-california-1733238 For those of us not literate in the field, how significant is this and what are the...

Find the problem and solution below; Now the part i do not seem to understand from the given solution is the negative value i.e to be specific ##-0.06## In my understanding we shall have ##5## possibilities with each giving the correct mean value of ##3.48## which implies ##+0.06## from the...

I have 100 random real (even rational with only one decimal, like average temperatures of months at a particular weather station) numbers. With them I compute the arithmetical mean and the median. It is a (very) small probability they are the same number within let's say 0,1 or 0,2. Question...

In Sakurai Modern Quantum Mechanics, I came across a statement which says probabiliy flux integrated over all space is just the mean momentum (eq 2.192 below). I was wondering if anybody can help me explain how this is obtained. I can see that ##i\hbar\nabla## is taken as the ##\mathbf{p}##...

If ##f## is a "spatially homogeneous" scalar field on spacetime ##ds^2 = dt^2 - a^2(t) \delta_{ij} dx^i dx^j## then show that ##\nabla^2 f = \ddot{f} + 3H \dot{f}##. Should be easy if I knew what the condition on ##f## is, i.e. ##\nabla^2 f = \partial_{\mu} \partial^{\mu} f = \ddot{f}- a^{-2}(t)...

1. You are working in a company facing attrition problems of the customer service representatives for the past five years. The company president proposed that if the attrition rate is at least 10 per month, then the salary scale, compensation package, and professional development programs for...

1. The Head of the Mathematics Department announced that the mean score of Grade 11 students in the second periodical test in Statistics was 89, and the standard deviation was 12. One student believed that the mean score was less than this, randomly selected 34 students, computed their mean...

I have a scatterplot that I'm trying to extract. I found 54 values out of 55. There is one "missing" value, probably because it is overlapped and I can't actually see. I have the MEAN and Stand Dev of the 55 values. Is there a way to reverse find the one that is missing? I mean, is there a...

I would like to practice SQL and install MySQL, one of the most popular open source DMBS. MySQL workbench can also to be installed and used as a visual GUI to interact with MySQL which in turns interacts with the database. My question: is MySQL a server application? If so, what does it mean? I...

Hi, I'm new to the quantum world, and would like to know why mathematically can we say that for mean value of measurment: <T>=<phi|T|phi> ?

See attached question and markscheme. Solutions Now they give the Mode as ##1## i am not getting this... My understanding 'maybe its the English used' is that we have ##0## children living in 3 houses, 7 houses have ##1## kid each bringing total number of kids to 7!, 5 houses have ##2##...

Can we have two tangents (two turning points) within the given two end points just asking? I know the theorem holds when there is a tangent to a point ##c## and a secant line joining the two end points. Or Theorem only holds for one tangent point. Cheers

if someone want to explain to me what is an upright image ? , and what are the other adjectives to define an image in geometric optics and their meaning , Thanks .