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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0
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2answers
87 views

preliminary evaluation for forecasting models

Suppose I would like to use a method for data prediction, and that I have some empirical data (i.e., sequence of samples of the form [time, value]). Would it be possible to know in advance, based on ...
1
vote
1answer
83 views

Waveform filter - what's in the black box?

I'm trying to come up with an algorithm or filter that has the i/o characteristics in the image below (waveform plotted from audio data) .. I input a sine wave or saw and the resulting graphic is an ...
1
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0answers
33 views

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 ...
0
votes
1answer
50 views

Graphically representing low number of infractions against high activity volume

I have been presented with a dataset that looks at work volume and safety infractions. A sample table: A sample chart: The issue we are having is trying to graphically represent it so that ...
0
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0answers
385 views

how to calculate a curvature/angle of best fit line segments

I have data points from a power spectrum (fft) output that look like the image below. A characteristic of the data seems to be a heavy slope and then a flattening out. I would like to be able to ...
1
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1answer
1k views

Understanding a Density Plot

I am currently plotting density plots in R to view the distribution of my data. An example density plot is here I understand N is the number of values in the data set and bandwidth is the the ...
3
votes
3answers
281 views

What would this curve be called?

In an resistor-capacitor circuit, the voltage stored is measured by taking the two values in Farads and Ohms - and the curve looks like this: What would this curve be called, logarithmic? ...
0
votes
1answer
126 views

Fitting two separate curves to a graph consistently?

I have a set of graphs with a large primary peak and a secondary peak that intersects the first and I want to fit two curves (one per peak) and find the point at which the two curves intersect for ...
1
vote
1answer
356 views

Curve fitting with upper and lower bounds for derivatives

I compute (at a great cost) upper and lower bounds $f_u(x)$ and $f_l(x)$ of an unknown function $f(x)$ at points $x$ in $[0,1]$. Now I am interested in an estimation of the derivative $f'(x)$. I ...
2
votes
2answers
151 views

weighted ratings

I have a form where users can rate presentations and they can say how knowledgeable they are on the subject. The range for both sets is 1-5. (1 being lousy and 5 being great) So for example, a user ...
1
vote
1answer
356 views

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: ...
9
votes
4answers
2k views

Polynomial fitting where polynomial must be monotonically increasing

Given a set of monotonically increasing data points (in 2D), I want to fit a polynomial to the data which is monotonically increasing over the domain of the data. If the highest x value is 100, I ...
2
votes
1answer
6k views

Boxplots and bar graphs

I'm studying for the GRE and came across several questions that I was unable to answer in a practice booklet, even after looking at the answer and trying to work backwards, and searching google and ...
1
vote
2answers
134 views

Trying to find a meaningful statistical indicator to reflect user interaction with a website

A given user can interact in multiple ways with a website. Let's simplify a bit and say say a user can: Post a message Comment a message "like" something on the website via Facebook (after that we ...
1
vote
1answer
132 views

problem constructing an equation that connects variables

need a suggestion/advice/inputs from the mathematicians here. I have collected data of number of instructions/sec executed by a processor every second, number of loads/stores performed every second ...