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11
votes
2answers
18k views

How do you find the uncertainty of a weighted average?

The following is taken from a practice GRE question: Two experimental techniques determine the mass of an object to be $11\pm 1\, \mathrm{kg}$ and $10\pm 2\, \mathrm{kg}$. These two ...
2
votes
2answers
136 views

Question about interpreting PDG particle cross section data sets' metadata fields

I have some question about interpreting PDG particle cross section data sets' metadata fields. The data sets I'm having questions for are http://pdg.lbl.gov/2011/hadronic-xsections/hadron.html For ...
11
votes
1answer
1k views

Which areas in physics overlap with those of social network theory for the analysis of the graphs?

I am studying social networks in terms of graph theory and linear algebra. I know that physicists have published and worked a lot in this field. This causes me to assume that there are sub-fields in ...
11
votes
2answers
980 views

Use of Monte-Carlo simulation in High-energy Physics

I've been doing some research into the analysis used in particle physics when determining the significance of a finding (e.g. the recent Higgs candidate was announced as a boson in the 125-126 ...
5
votes
6answers
6k views

How to guess the correct fitting function to some data?

Imagine we are plotting some date points $\left(x_i,f(x_i)\right)$ that we obtained experimentally, and that we want to know what $f(x)$ is. The way to do this is to use some software and try to fit ...
5
votes
2answers
1k views

What is meant by “combinatorial background” in experimental high energy physics

My guess is that they find a certain tracks coming from a certain source by "combintaorially" selecting all track pairs and finding their invariant mass. If this is true, of which I am not sure, how ...
0
votes
1answer
1k views

Terminal velocity of a steel ball in water [closed]

I am investigating on the terminal velocity of steel balls moving in water. I used the balls with different diameters, such as 3.17mm, 6.02mm, etc. And I used a full-filled 1L graduated cylinder. I ...
15
votes
2answers
2k views

Did the researchers at Fermilab find a fifth force?

Please consider the publication Invariant Mass Distribution of Jet Pairs Produced in Association with a W boson in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV by the CDF-Collaboration, ...
4
votes
1answer
473 views

How do I calculate the experimental uncertainty in a function of two measured quantities

I am performing an experiment where I'm measuring two variables, say $x$ and $y$, but I'm actually interested in a third variable which I calculate from those two, $$z=f(x,y).$$ In my experiment, of ...
5
votes
1answer
314 views

Advanced data analysis in Physics experiments

I know that regression, chi-distribution, covariance, error propagation, etc. are frequent tools for experimental physicists. So, I'd like to know if advanced statistics topics are used in data ...
3
votes
1answer
264 views

Rutherford Experiment - practical and theoretical questions

I performed the Rutherford experiment the other day, using Au thin foil of $2\,\mathrm{\mu{}m}$, a source/gun of α particles (241Am) and a detector/counter. α particles were shot from the source ...
3
votes
1answer
776 views

Fitting to a high density scatter plot

I am trying to do a crude particle identification, using a Bethe Bloch tenchnique. Here is a plot I made from the data that I have From what I've read, the standard method to identify charged ...
-2
votes
2answers
99 views

Standards for scientific metadata in common-use image formats? [closed]

I have a bunch of JPEG, JPEG2000 GIF and PNG files that in theory could be used for some types of science analysis if there were temporal and spatial information in them. Years ago, I had looked into ...
5
votes
1answer
442 views

Finding coefficient of proportionality

Recently in my AP Physics class I did a lab in which I measured k for a spring by setting up an oscillating system with it, and timing the period, repeating for different masses. Since ...
3
votes
1answer
955 views

Lab observation correct? As distance decreases, velocity increases, stderr decreases

The experiment goes like this: Allow a moving cart to move from the top of an incline plane ($x_0$) downwards. The time taken will be recorded by the picket fence (those things you see wired up). ...
2
votes
1answer
156 views

What are anticipated events and experimental uncertainty?

I am working on this lab that involved gathering data from two different sources. It involved gathering reaction times from a device and from a web application which was put into our data sets. It is ...
1
vote
1answer
125 views

Variance of Nested Experimental Uncertainty

I have to find the uncertainty of a quantity $Q$ doing two mean values. For example for a set of parameters I measure ten times $Q$, I obtain a mean value $Q_1$ and variance ${\rm Var}(Q_1)$. Then for ...
0
votes
2answers
126 views

Help Writing An Equation [closed]

Truthfully, math past basic algebra was never my strong suit even though I went through stats in college. So I have to write an equation for this for a program and could use some help. I am reading ...
0
votes
1answer
271 views

Dealing with experimental data

I have some experimental data about a value $n$, now, I am supposed to give, in the ending, a single value with an error: $n=a\pm b $. I have originally 6 values of $n$, each one comes as an indirect ...
0
votes
3answers
437 views

Sunspots formula

I used the package 'EUREQA', version Formulize, to analyse the monthly smoothed sunspot timeseries from 1750 till 2010. It gives me a simple formula, with 8 coefficients, that match data with a ...