The data-analysis tag has no wiki summary.
13
votes
2answers
1k 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, ...
7
votes
2answers
220 views
How to predict how much data to collect
The same question on CrossValidated
Apologies if I'm being a bit vague in what follows, I've been asked to keep certain aspects of the experiment confidential for the time being.
An analogous ...
6
votes
2answers
286 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
1answer
5k views
How do you find the uncertainty of an 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 ...
5
votes
1answer
176 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 ...
5
votes
2answers
262 views
How are the HEP experiments' invariant mass plots generated?
I am experimenting and playing around with some data, and I'm having trouble seeing how to generate invariant mass plots.
The data I have has a bunch of events, and variables such as ...
4
votes
1answer
387 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 ...
4
votes
1answer
183 views
Pendulum: Deduce proportionality from experiment
I know, very easy for all of you, but I'm a beginner in physics ... ;)
I have to work with the mathematical pendulum. After some experiments (changing mass, chaning pendulum's length etc.), I could ...
4
votes
2answers
192 views
What do “local” and “global” mean when talking about standard deviations in experimental particle physics?
I found the following sentence:
The excess is most compatible with a SM Higgs hypothesis in the vicinity
of 124 GeV and below, but the statistical significance (2.6σ local and 1.9σ
global after ...
4
votes
0answers
66 views
Design of experiments to determine proportionality
A common result of theoretical analysis in physics is some sort of relation derived from physical parameters and typically expressed in the form of a non-dimensional parameter. These scale relations ...
3
votes
5answers
1k 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 ...
3
votes
3answers
129 views
What are the easiest ways to get data out of a FITS file without a library?
There are FITS libraries for most programming languages (see this list), but FITS is a simple enough format that it should be pretty easy to extract data without the need for such libraries or ...
3
votes
1answer
86 views
What algorithms are used for track reconstruction in cloud chambers?
In particular I'm interested in any algorithms that can separate multiple tracks from one another reliably.
3
votes
1answer
354 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 ...
3
votes
1answer
40 views
How to determine frequency components present in distorted signal, with the set of possible components already known?
I am trying to choose the best approach to digitally analyse a signal, which is a mix of an unknown number (but less than 16) fundamental signals at specific frequencies (e.g., sines).
The goal is ...
3
votes
1answer
161 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). ...
3
votes
1answer
85 views
Measuring tensor rank of the Higgs resonance
The Higgs boson is the first scalar field ever measured that is fundamental rather than composite. How do high-energy physicists determine that a given resonance in the statistics is either a scalar, ...
3
votes
0answers
90 views
Obtaining point of application of Ground Reaction Force with use of a hyperstatic load-cell array platform
I'm looking for the theory of an experiment that is giving me a hard time to perform.
I have an instrument composed of a rigid horizontal square plate rigidly supported under each corner by a ...
2
votes
2answers
98 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 ...
2
votes
0answers
138 views
Production vs. Collection, and Contaminants vs. Depositions, what might be missing in cold fusion research
I though cold fusion and LENR were discredited, but just a few days ago I found out that NASA is claiming LENR is real. So I thought if they're detecting something, what could it be, and why wasn't it ...
2
votes
1answer
122 views
Peak deconvolution [closed]
I need some help understanding how much information I can pull out of this data. I have a sample made up of two materials. Materials A and material B. Then I took a picture of the sample.
The two ...
2
votes
0answers
134 views
How do I do error calculus right using gnuplot as an example?
Given is a set of measurements with their respective errors for example an energy spectrum. In gnuplot one is to fit a function $ f(x;\{p_i\})$ depending on a variable $x$ and on fit parameters $p_i$. ...
1
vote
3answers
240 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 ...
1
vote
1answer
34 views
Interpreting the results
I have preformed the muon lifetime experiment at my uni's lab, and got the data. It's text file with 8190 numbers. My TDC unit was set so that the time gates were at 10 $\mu s$, and it has 8192 ...
1
vote
1answer
75 views
Uncertainty in Acceleration given the uncertainty in position
I had a motion detector record the position of a dynamics cart and automatically plot Position vs Time and Velocity vs Time plots in Logger Pro on the computer. If the instrument uncertainty in ...
1
vote
1answer
81 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 ...
1
vote
1answer
197 views
Graphing measurements with uncertainties
I need to draw a graph of measurements of time for a ball to drop on an inclined plane, with error bars, along with lines of best and worst fit. The problem is that I need to do this on the computer ...
1
vote
1answer
57 views
More points vs. precision
I have a dilemma.
In my lab exercise, I was measuring spectra with HPGe detector of several sources (gamma spectroscopy). To determine the energy of the unknown spectrum I first needed to calibrate ...
1
vote
2answers
682 views
Physical interpretation of y-intercept in a Current vs Voltage graph
So I collected current and voltage data from a simple circuit with a power source and a resistor, using a multimeter. I created a graph for this data using excel and got the y-intercept (which is ...
1
vote
0answers
43 views
How to calculate the correct coordinates from a distorted video of a projectile?
I am working on a high school project that is related to projectile motion. I am exploring how exactly the position of the center of mass affects the trajectory of a long but thin, javelin-like ...
1
vote
0answers
94 views
Digital camera as a measurement device [closed]
It is know that digital camera is not the best device for quantitative measurements. However, it is often used in all sorts of atmospheric physics research, maily due to:
Low cost and availability. ...
0
votes
3answers
61 views
fit funtion to the Sun electron fluxes data
I'd like to fit a function to the Sun's electrons flux data (blue dots), please note that x,y axis are in the log scale. The green dots are the "best" fit from the gnuplot program. I have taken the ...
0
votes
3answers
98 views
How to find exponential values
I have a power equation for flow between two circular disks on a common axis as stator and rotor, which follows,
$$P = \frac{n^a}{G}\tag{1}$$
Where:
$P$ = power,
$n$ = revolution (1200 rev/min),
...
0
votes
1answer
40 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
1answer
113 views
Analysis of the impulse of 2 colliding carts under the effect of magnetic repulsion
Hi there! I have a question about an experiment that was conducted. It is related to momentum.
2 carts were put on a track on opposite sides. They were then propelled towards one another at ...
0
votes
2answers
298 views
Microsoft Excel not graphing $x = y^{1/2}$
The experiment was relating the period of one "bounce" when you hang a weight on a spring and let it bounce. I have this data here, one being mass and one being time.
The time is an average of 5 ...
0
votes
1answer
213 views
Implementing a black-body using Planck's Law in a 3D ray tracer
1_ In one of my software projects, I need to implement Planck's Law in terms of wavelength. I can't be sure if it's right because I've seen different variations of it, and all the implementations ...
0
votes
1answer
146 views
Filtering and extracting turbulent data from instantaneous dataset
I have collected data on flow velocity at 1 Hz sampling rate for 25 hours using a high resolution acoustic Doppler current profiler (HR-ADCP).
how I can decide up to which period is the mean ...
0
votes
0answers
22 views
Removing seasonal and non-seasonal oscillations with least-square method [closed]
I was trying to find help online, but with no luck :( Hoping you will help me!
I have data containing sea temperature with depth. With data I need to remove seasonal and non-seasonal oscillations by ...
-1
votes
1answer
83 views
Fitting of exponential data gives me a constant function [closed]
I conducted an experiment, where a capacitor is discharged over a (big) resistor for $t$ seconds and then the remaining charge is measured with a ballistic galvanometer. The data I have is:
...
-3
votes
2answers
52 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 ...
