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.
Questions tagged [data-analysis]
1056 questions
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How to symmetrically adjust data by removing certain value
Say I have a data set in the following format: {a:200, b: 100; c:400}
The sum of a, b and c equals 700. Now, I have another value which is supposed to be the actual total say 500.
How do I adjust this difference of 200 in the initial data set (the…
dev_musings
- 111
- 2
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1 answer
Find median given large amount of data
Listing all the possibilities would take time. Would there be a faster and more efficent way to find the median?
user159778
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$y=\sqrt x \rightarrow \ln y = \ln x$ problem
So I had some raw data, and it looked like there was a square root relation.
I plotted graphs of $y=\sqrt{x}$
They look kind of straight. So doing the algebra and taking the ln of both sides, we get $\ln y=0.5 \ln x+\ln k$
I then plotted the graphs…
Jim
- 1,210
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1 answer
How to work out the formula that connects several numbers
I have an interesting problem. Say I have lots of datasets like this:
a = 21
b = 23
c = 58
d = 498
etc (lots of other values)
X = 85
I need to find the formula that derives X from a, b, c, d etc, with the added complication that I don't know…
Bluefire
- 1,668
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1 answer
How do I creat a box and whisker plot?
I know you have to create a box around the median of a data set of numbers, but I do not know where the end of the box would be placed. Please help!
user111737
- 171
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1 answer
Problem with significant figures
I know that if I am multiplying/dividing my answer is the least number of significant figure in the data and if I am adding/subtracting my answer is the least number of decimal places i the data but what if I have a constant for example:
If I want…
user134345
- 97
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1 answer
Given sample data with three data points, how do I predict or guess the 3rd data point when only given two data points?
I'm tracking data on a backup job that runs nightly on our server and using the historical data to predict data and job time growth. I have the following three data points for most of the records: Data backed up (in Bytes), Total Job Time…
music2myear
- 113
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grouping of skewed dara
I have a set of data composed of the measurements of spaces. There are 2 distinct sizes represented in this data set.
(distinct in that the larger size is larger by some unknown multiple)
I am looking for away to separate the items such that the…
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1 answer
Function form to fit a nonlinear trend
I'm trying to guess a function that would fit the non-oscillating part of the following curve:
I tried something in the form of $y = 1 - e^{-ax}$ and $tan^{-1}(ax)$, but it didn't work since the trend becomes horizontal for extremely low values of…
ValientProcess
- 231
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What is the function called?
I have some data to fit that looks like the blue curve, would anyone know what is it called or just the equation for it?
Some extra info:
I`m trying to fit some data from an electronics experiment dealing with impedance (in alternating current,…
Lyu
- 111
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Fitting the OPLS forcefield dihedral to ab initio data
Background
I am trying to fit a set of energy vs. dihedral angle data obtained from the quantum mechanical software Gaussian. The data was obtained by rotating a certain group of atoms 10 degrees at a time relative to another certain group of atoms…
Marcus
- 13
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question about structural casual model
So I am struggling with understading Structural Causal Modelling. I have the following model
$$z=Nz$$
$$y=-z+Ny$$
$$x=2*y+3*z+Nx$$
I have the following variable values
$$Ny=0; Nz=0; Nx=0; z=5 $$
If i intervene the variable $y=7$ what is the result…
Boris Grunwald
- 431
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2 answers
Curve fitting: $a f_1(x)+b f_2(x)+c f_3(x)+d f_4(x)$
I want to fit my data $y$ with a method such as
$$a f_1(x)+b f_2(x)+c f_3(x)+d f_4(x)$$
However I don't know how to obtain coefficients $(a,b,c,d)$ of the known functions $(f_1(x),f_2(x),f_3(x),f_4(x))$. I don't know least squares very well.…
newzad
- 4,855
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1 answer
How do I find an equation for this data sample?
I have gathered some data and I'm trying to find an equation for it. There are two variables, as you can see in the table below. I've noticed the result is equal to the x value as long as x <= y. Then, for any given y, the results follow a very…
Skaidan
- 11
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What does a logarithmic scale graph express that a linear scale one does not?
...essentially, why would someone want to look at a logarithmic scale graph? What can be derived from a logarithmic scale graph that makes it worthy of presentation in addition to a linear scale version?
At worldometer on Coronavirus there is a…
user664833
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