Questions tagged [data-analysis]

Use for question relating the the techniques of data analysis.

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0answers
21 views

What should be the real error band of a fit function?

This is a question concerning data analysis. It could relate to particle/nuclear physics or other field. Please note that this question has nothing to do with technical problems, and is more of a ...
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3answers
76 views

How to Interpolate When Reading a Scale

Suppose, I am taking measurement with a scale whose least deviation is 1mm. the length of something seems to lie between 44mm to 45mm. But my instinct says, it's 44.7mm. So, the question is I should ...
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5answers
126 views

Calculating mean velocity: using time or velocity? [on hold]

Background I have been running tests which involve timing an object moving a certain (fixed) distance, $s$. Each test has been repeated 3 times, and the 3 times ($t{_{1}}, t{_{2}}, t{_{3}}$) for the ...
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0answers
22 views

Fitting power law with shift to experimental data

I have some data that I can tell visually that scales like a power law. However, the $x\rightarrow \infty$ and $y\rightarrow \infty$ asymptotes of the data are nonzero. I should thus fit the data to ...
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16 views

Data Adaptive technique

I read in many research paper about the data adaptive analysis techniques. I tried a lot to find the meaning of 'adaptive' in data analysis. What is the main function of the adaptive nature of the ...
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0answers
25 views

entropy and redundancy of data

I have a quick question about the redundancy of data and the information that it represents. A means of evaluating the amount of information contained in the data is evaluated with a notion of entropy....
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2answers
51 views

Least-square fitting to data (sine function): what is the error of the derived fit parameters?

I have a set of data. I want to fit it to a sine function of the form : \begin{equation} f(x)=A sin(\omega x+B)+C \end{equation} I use the least-square method to find the appropriate fit-parameters ...
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2answers
53 views

What software programs are recommended for background extraction and peak fitting?

I have an energy spectrum for various gamma sources. What software programs are recommended for background extraction and peak fitting in this case?
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28 views

Signal parameter estimation in PyCBC

I have a gravitational wave signal (strain vs. time). And I want to find out the corresponding parameters of the compact binary. But I do not know how to create injection for this signal in PyCBC. ...
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0answers
19 views

What Dimensionality Reduction method I can follow on a dataset that has Physics Parameter?

I am trying to model data related to Locomotive Train. We have a various set of parameters and we have the possibility to generate a few more parameters from this. Our model is currently using a lot ...
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1answer
29 views

Power law correlation between with three parameters

I made a CFD model of the Centrifugal Atomization Process. Studies show that the mean particle size $d_{32}$ can be expressed as a function of the three operating dimensionless numbers (Reynolds, ...
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1answer
32 views

Normalize accelerometer data based on non-central location

I am trying to "normalize" accelerometer data for a sensor that is not centered on a car. In the image below, you can see how centripetal force changes based on location. In my case, I only have one ...
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1answer
38 views

What is the meaning of true value and uncertainty from a measurement?

I am taking the following example: Lengths of an object are measured as : 5cm , 5.2cm , 5.1cm , 5.5 cm. Calculate the true value and the error . The answer is True value = 5.2 cm error = 0.15 ...
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2answers
119 views

Why is the resolution or measurement uncertainty of $G$ so bad?

I sorta know how the Cavendish apparatus works, and I know that "Gravity is an extremely weak force" for subatomic particles in comparison with the E&M or nuclear forces that act on these ...
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0answers
29 views

Uncertanty in Chi-squared measurements, spectra-like

Let's say I have some observational data. For example: in a certain wavelength interval I measure the flux, 10 000 points, and I have the uncertainty for each one of them. For example: ...
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4answers
2k views

How do I fit a resonance curve?

In an experiment, I collected data points $ (ω,υ(ω))$ that are modeled by the equation: $$ υ(ω)=\frac{ωC}{\sqrt{(ω^2-ω_0^2)^2+γ^2ω^2}} \,.$$ How can do I fit the data to the above correlation? And ...
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4answers
7k views

How do we know the LHC results are robust?

Nature article on reproducibility in science. According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. ...
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11 views

Visually comparing variances

I have a dataset containing 8 categories, I now want to visually compare the variance between the categories. The most common approach would be to use box plots or violin plots but I would like to ...
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1answer
39 views

What is BVI Photometry and how is it used?

I searched for data about Cepheids light curves (often used as standard candles for measuring distances), and found that all of the data comes in a form of "BVI Photometry" or "BVI Photoelectric ...
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1answer
51 views

Origin of XRD Peak Asymmetry

I have been doing an introductory XRD experiment in which we measure the crystal spacing of a simple lattice (LiF) and as usual obtained data for intensity against two theta. Ideally the peaks should ...
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2answers
77 views

Do I force the intercept to zero when determining the coefficient of friction?

I have made these measurements of kinetic friction force vs normal force: I want to measure the coefficient of friction as the slope of the line. Unfortunately the line does not pass through $(0,0)$. ...
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0answers
35 views

Mathematical Resolution of Overlapping Signals

I would like to take the opinion of physicists (my area is chemistry). During instrumental analysis, the output is a instrument response vs. time. Each peak corresponds to a molecule which is ...
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0answers
26 views

Why is this version of Fourier deconvolution justiifed?

As I understand it, one typically performs Fourier deconvolution for the data produced by some instrument of a linear system by: Taking the observation of some unit impulse signal $m$, with the ...
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1answer
62 views

Error propagation and data linearization

I am fairly new to teaching error propagation to students but came across a question I couldn’t answer myself. Say we have a set of data that produces a parabola. In order to linearize the data and ...
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2answers
83 views

Big Data Handling at the LHC

My understanding is that much of the data that is is collected at the Large Hadron Collider is similar to that in the image below, and that a vast amount of the data contains little of specific and ...
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0answers
42 views

How to Mathematically Compute Spectral Power Distribution for Each Visible Wavelength in Spectrum?

I'm a CS student and been working on a conversion program that includes computing Spectral Power Distribution (SPD) from each visible wavelength in color spectrum. Here's the formula : $$X = \int_{...
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0answers
27 views

Observed Data for Asteroid Lightcurve

I am looking to find out more about writing statistical analysis programs in python for astronomy problems and was recommended that I could analyse asteroid light curves for an introduction into the ...
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7answers
1k views

When to average in the lab for indirect measurements?

I am measuring distance and time to calculate the velocity. I repeat the experiment 10 times. What is better, to first calculate the average of distance and time and then the velocity, or to calculate ...
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0answers
40 views

How to fit mean squared displacement data from nanoparticle tracking analysis?

I am trying to independently analyze raw nanoparticle tracking analysis (NTA) data, but my diffusion coefficients calculated directly from x and y pixel values only moderately correlate with reported ...
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1answer
98 views

Double slit experiment/ fitting data to complicated sine function and vice versa [closed]

As part of analysing the double slit experiment, I've recorded position values for a number of minima and the central peak position. Also, I've conducted a single slit experiment (with unknown width)...
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2answers
67 views

Removing zero-counts in exponential decay measurement

I'm doing an experiment where I'm measuring the mean-lifetime of muons. I have a set of data points for the number of decays against time, resembling an exponential distribution (of course). But in ...
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0answers
84 views

Where to find databases from physics experiments?

In some lecture I want to write about data analysis in physics I want to show some real uses of data analysis tools in the analysis of data from real experiments. I tried to search but I couldn't find ...
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1answer
36 views

What do the points on a Dalitz plot represent

I have read that a Dalitz plot is nothing but the plot of $m_{12}^2$ vs $m_{23}^2$, and that the dots correspond to "events". However, this doesn't really tell me anything. My question can boil down ...
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2answers
69 views

Estimate of the period of noisy “event counting” data

I have a set of experimental data, which come from a periodical event. More specifically, these are detections from a single photon detector, so there is no intensity, I only have the timestamps of ...
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0answers
44 views

Data-analysis (Uncertainty and errors)

This is just a data anlysis question but I thought you might need an introduction. In order to calibrate de Michelson interferometer one needs to find $\eta$ in the relation: $d = \eta D_\mu$ where $...
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1answer
35 views

File with particle decay data [closed]

Does anyone know of a computer parsable file that has basic physics and decay data for (quite many) observable particles, such as mesons, barions, heavy leptons and $W, Z, H$? To clarify the data I ...
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0answers
22 views

Does the vertex efficiency include track reconstruction efficiency?

Consider a document of ATLAS collaboration on displaced vertex level efficiency. On the first two pages there is a description of cut-offs required to background free displaced vertex reconstruction. ...
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1answer
50 views

What is the significance of a $\chi^2$ analysis?

What is the merit of $\chi^2$ analysis in the laboratory experiments? Why is so much emphasis put on it?
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1answer
234 views

Binning or just skipping values in a simulation to avoid autocorrelation

Given a set of data from a generic Montecarlo simulation $x_i$, $(1=1,...,N)$, autocorrelation is expected to happen between data points within relaxation time $\tau$ (correlation time) distance ...
3
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1answer
110 views

Jackknife estimation of variance very different from expected variance

I was rapidly introduced to the Jackknife procedure for data analysis and I stumbled upon a problem I'm not able to understand. Let's consider a very simple case: the estimation of the average of a ...
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2answers
81 views

Is there any experiment that doesn't have a finite countable number of outcomes?

There are a lot of random variables in physics that are, in principle, continuous and unbounded (canonical examples: time, position along each direction). In practice, it is my understanding that the ...
2
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1answer
152 views

Exclusion limits on particle dark matter

I'm trying to make sense of how the upper limits of the cross-section of particle dark matter (WIMPs) are computed, like in the figure below. This is taken from an article on dark matter searches. ...
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1answer
54 views

Determining Threshold Voltage and Plateau from experimental data

I’ve been trying to figure out how to interpret the following data from the Geiger muller tube There are only seven data points. Where does the plateau begin? Has the data collection begun after the ...
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1answer
38 views

Tracking efficiency for experiments at CERN

For various experiments (e.g. ALICE, CMS etc) at the CERN-LHC, people talk about tracking efficiency. What exactly is this tracking efficiency? How different is it from reconstruction efficiency?
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1answer
91 views

Convergence tests for experimental data

I ran a simulation for the critical density at which traffic flow transitions from laminar flow to start-stop-waves. The results for different road lengths are: From the graph we can see that the ...
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0answers
43 views

Question about statement of uncertainty

I have a doubt about uncertainty of a measurement. I have a sample of a specific material which is my reference material and it is calibrated and NIST traceable. This sentence is in its data-sheet: ...
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0answers
67 views

What are common methods to remove discretization on experimental measures?

I have some experimental data, and since the measurements are digital, the data is discretized/quantized/rounded/truncated. I need to know if there are general methods, or common methods, to "smooth" ...
4
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1answer
116 views

What causes the 20 second period in LIGO data?

I download LIGO data on GW150914 (gravitational waves) via the code in Mathematica ...
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0answers
823 views

Parallel Axis Theorem Experiment

I am currently working on a physics experiment to confirm the parallel axis theorem. To do this, I have the following setup: In this experiment I change the distance between the centre of the ...
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1answer
652 views

Moment of Inertia and Mass Experiement

I am currently working on a physics project to experimentally confirm the relationship between mass and moment of inertia. The experiment is setup as depicted: In this experiment, $r1$ and $r2$ are ...