Questions tagged [data-analysis]
Questions on the use of mathematical techniques to extract properties from given data. Consider if your question might be more suited for Cross Validated (stats.SE) instead.
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Which type of numerical differentation (forward, backward, central) is better suited for magnetic field data
We have three types of basic numerical differentation: Forward, Backward and Central defined as such:
Forward difference (uniform grid)
$\frac{df}{dt}\Big|_{t = t_i} \approx \frac{f_{i+1} - f_i}{\...
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Doubt about effect of Standard Scaler on persistent homology
I’m currently studying persistent homology, and I’m quite new to the topic — so please forgive me if this is a naive question.
I’m trying to analyze 2ドルD$ data where each axis represents quantities ...
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Data Analysis, relative error and uncertainties
I have some data analysis that I need to do, but I am not sure how to go about using relative error, or if I should even use it at all.
I have an experimental result with uncertainties calculated, and ...
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How to define the dimensionality and manifoldness of point data?
Consider the following scenario. A set of points is uniformly sampled from the surface of a sphere. Then a perturbation noise is applied to each point, displacing them in space.
As the magnitude of ...
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Looking for a crisp argument about the correlation with a complementary event
Assumme a variable $x$ is positively correlated with an event $A,ドル by which I mean that $\rho_{x,1_{A}} > 0,ドル where $\rho$ is the correlation coefficient and 1ドル_{A}$ is the indicator function of ...
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Sampling theory for non-differentiable functions?
I am interested in sampling fractal like functions. In three dimensions, but for now let's focus on the real line case.
Smooth case
If I have a smooth function $f$ I can generate a sampling of $f$ by ...
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Why is it necessary to center data before performing PCA? [closed]
I'm trying to get a deeper understanding of Principal Component Analysis (PCA), and I keep coming across the point that we must center the data around zero before determining the principal components.
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UV map of a sphere with perspective given perfect distance and fov
This is my first post here, and I'm nowhere near the level of math knowledge everyone else is, though I am still fascinated by 3d (and color, though here that's irrelevant) related fields.
I've been ...
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Handling Structurally Missing Data (SMD)
I am seeking advice on how to handle a specific type of systematically missing data (SMD) variable in a longitudinal survey dataset. From what I understand, SMD in survey-related data is often ...
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Condition number of a matrix do not increase when data is removed
If anything, it will most likely decrease.
Let $A$ be a matrix with $m$ rows and $n$ columns ($m\le n$) and $\sigma_m(A)>0$. Let $A'$ be the same matrix with one row removed. Their condition ...
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A concentration inequality for projections
I seek a probability bound for the equivalent event: $\vert \vert P_{X} u - P_{\mathbb{E}\left( X \right)} \mathbb{E} \left( u \right) \vert \vert^{2}$ $<$ upper bound. Something like a Hanson ...
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How do you analyze integer sequences in general?
I know how to do it for polynomials and geometric sequences but I can't figure out how to do it for data made from the sum of and exponential term and a polynomial.
I am studying for the EDPT which ...
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Fitting general but "smooth" convex shape to points
I am aware that there are algorithms to fit, say, an ellipse to a bunch of given points on a plane. For instance, this SO question has answers which feature both literature on the algorithms and ...
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How can I predict when will my water tank be empty? (Linear regression problem)
I am trying to predict the date when my water tank will become empty using linear regression. I have a sensor that tells me how much my tank is full in percentage. I take a single measurement every ...
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Derivation for least squares regression
This is a graph showcasing the lemonade sales as per temperature.
Multiple data points: $(30, 90), (35, 100), (37, 110), (42, 125), (50, 140),ドル etc.
Now, as I have been studying the equation of a line....