Questions tagged [data-analysis]

Use for question relating the the techniques of data analysis.

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16 views

Modelling a spring powered car - using a cubic

I've designed, built and tested a mousetrap-powered car. However, I'm having trouble with how to fit the results. I claim an approximate fit to a displacement-time graph of the car should be a cubic ...
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1answer
31 views

Optimizing Muon Lifetime Data

I performed an experiment which measured the lifetime of a muon. The apparatus was very archaic and susceptible to disturbances, which means that there would inevitably be some unreasonable data ...
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1answer
27 views

Power Spectrum Density of real valued time series data

There are real valued time-series data X(t) and corresponding auto-correlation function ACF(t)=$\left<X(0)X(t)\right>$. As written in wikipedia, Power Spectrum Density (PSD) can be calculated ...
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14 views

Optical pyrometry data analysis and manipulation

Today I was doing my Optical pyrometry lab experiment with a following setup. I had a wolfram wire light bulb connected to a circuit in which I could control voltage. Using the pyrometer, I was to ...
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1answer
42 views

Homework/Lab question about my data analysis

I in the experiment, I have tried to find a relationship between a quantity B and quantity I. First I plotted the raw data into a graph and tried different curve fits in excel. This is the graph that ...
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97 views

Graph analysis of accelerometer data

I used my mobile accelerometer sensor to collect data from a moving bike where I held it in my hand in a way that the smartphone sensor +Y axis is in the direction of the moving bike always. This can ...
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1answer
28 views

Can we plot a FFT for a Decibel vs Seconds data?

I was plotting FFT for Decibel values corresponding to the time in which it was recorded using a DAQ for My project, The sample data looks like this, I was attempting to plot the FFT thinking that ...
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105 views

Light Bulb Resistance

If the voltage and current of a circuit containing a light bulb are measured using a multimeter after consecutively lowering the voltage (building of a data set), what (type of) function will describe ...
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32 views

How long should I record the data of walking acceleration for FFT analysis?

Seems there is no apparent frequency of walking activity (it should be approximately close to 2 Hz) Is it because the time of the data is too short? Here is my csv file:enter link description here
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1answer
41 views

How to subtract background from many spectra which were taken with different background intensity?

I have two spectra, a spectrum of background signal (let's call it Reference) and measured spectrum consisting of searched signal and background signal. The searched signal is a peak/s with various ...
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2answers
39 views

Calculating uncertainty in a fitted model

I am working on a project that requires the measurement of the Verdet constant of a material by observing a phase shift in the cosine squared model provided by Malus's law. I have recorded the ...
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1answer
51 views

How to combine several dependent predictions and get the best estimate?

I want to predict the value of some physical quantity $P$ at a time $t$ using actual measurements of $P$ acquired before and after $t$. The formula I use for making these predictions is: $$\hat{P}_{t}...
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68 views

Question about FFT analysis of a signal

In labs we had to measure the oscillations of a pendulum using an electric sensor. So basically, my data consists of time and voltage (which represents amplitude) pairs. The task was then to perform ...
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How exactly do you avoid fooling yourself?

In cargo cult science Feynman writes: "Millikan measured the charge on an electron by an experiment with falling oil drops, and got an answer which we now know not to be quite right. It's a ...
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Fitting Beta Emission spectrum data according to fermi function

I was trying to fit beta emission spectrum data to the equation $$\tau(E_e) \propto (E_e^2 - m_e^2 c^4)(Q-E_e)^2\frac{E/c}{\sqrt{E_e^2 - m_e^2 c^4}}.$$ However, on making a custom equation in Origin,...
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49 views

Linear Regressions vs Algebra & Averaging in Solving for a Constant

I'm current taking AP Physics, and in both of the labs performed so far (Snell's Law/Refraction and Galileo's Inclined Plane), I have been trying to calculate some constant from a linear relationship ...
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31 views

Step-like contribution to background $\gamma$ ray peaks

I'm reading the paper "Analytical functions for fitting peaks from Ge semiconductor detectors" by R.G. Helmer and M.A. Lee. For $\gamma$ ray peaks the spectral "background" in the region of a peak: ...
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19 views

How to physically interpret concave multifractal spectrum?

I try to investigate the damage of the metal surface with box-counting method (input data is SEM surface images) - some surfaces give a convex multifractal spectrum [f(α(q))=α(q)*q-τ(q) versus α(q)] ...
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33 views

Get the number of counts from a Gaussian that fits the logarithm of counts

I have n data to fit: $$x=[\text{channel}_1,\text{channel}_2,\dots,\text{channel}_n]$$ $$y=[\ln(\text{count}_{1}),\ln(\text{count}_{2}), \dots,\ln(\text{count}_{n})]$$ I'm considering a spectral peak ...
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26 views

What physical interpretation can we derive from this experimental step up?

(This is not a homework question!) An experimental set up shows 2 rigidly placed stands, with pieces of metal links joining with each other forming a chain. The chain is hung from the top point to ...
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62 views

Is there an index of common spectral lineshapes or table of common lineshape functions?

Is there an index of common spectral lineshapes in physics? Is there a program that automatically tries fitting to many different lineshapes? By line shape I mean the function that, given ...
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85 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
197 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
368 views

Calculating mean velocity: using time or velocity? [closed]

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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1answer
69 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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18 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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1answer
123 views

Entropy and data redundancy

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 the notion of entropy. 1) For ...
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2answers
84 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
76 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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31 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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21 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
37 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
34 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
78 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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129 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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32 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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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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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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15 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
82 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
91 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
265 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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40 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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1answer
199 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
91 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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29 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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47 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
145 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
73 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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