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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24 views

Deal with circular standard deviation

I have a sensor that gives me a direction of the target in degrees with a certain standard deviation and I use a circular probability density function (PDF) to represent probable locations for the ...
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0answers
15 views

Inversion of the Burrows Wheelers Transform

The "Burrows-Wheeler Transform" in signal processing is a transformation which is used in for instance data compression and pattern recognition. It can be described in mathematical terms as: Start ...
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1answer
14 views

Clustering elements according to covariance matrix

I'm doing a little bit of topic modelling (which is not really my area) with twitter tweets. The situation is the following: I have a (sort of) covariance matrix where the entrie $C_{ij}$ corresponds ...
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0answers
8 views

Methods for Extrapolating Data Close To Observations

I am aware of many different ways to go about interpolating between the values of known data points. However, whenever I come upon (I work in Quantitative Finance) the need to extrapolate data I find ...
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0answers
10 views

Random data generation from a bivariate distribution

Let $X$ and $Y$ be non negative random variables with joint distribution \begin{equation} F(x,y)=1-e^{-x}-e^{-y}+e^{-x-y-\delta xy}; ~~~x\geq 0,~~y\geq 0. \end{equation} How to generate a bivariate ...
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4 views

How do I find the weighted mean of maxima for a granulized data set?

I have a dataset for which I had to apply Wang-Mendel algorithm. The aim is to find the y value when x=14. I granulized and approximated the data and found the rules in the Mamdani format. Now I have ...
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0answers
12 views

Find a way to regression between two data which are NOT paralleled [on hold]

I have variables X and Y need to be regressed,shown in the following screenshot. I need to apply regression between X and Y. My problem is how to organize data to make the regression. For ...
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0answers
10 views

Negative data in DEA [closed]

How can I use negative data in slack-based measurement DEA model? Is this model translation invariant? What about non-oriented slack-based measurement model?
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0answers
12 views

translation invariance in DEA models [closed]

Are all non-oriented DEA models translation invariant? For example is the non-oriented Slack-based model translation invariant?
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3answers
45 views

Parameters estimation for gaussian function with offset

I've read the paper Least square fitting of a Gaussian function to a histogram by Leo Zhou on how to perform a Least Square Fitting of a gaussian function to a histogram. The Gaussian function used ...
4
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2answers
559 views

Way to compare three numbers with an algorithm.

Say I have values 10, 3, 6 What would be a way of finding a subjective difference between them. Or in other words, how close they are to each-other. So if i had 3, 2.5, 2.8; they would be close ...
2
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1answer
23 views

make the mean of 2 data sets the same

I am in the process of computing my student's final scores and for some reason I couldn't figure this step out: If I have 2 data sets of scores in the range [0,40] but one data set has a different ...
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0answers
28 views

Frequency domain analysis with limited time serie

I have a 1Hz measurement signal for a length of about 60 seconds. I strongly suspect/expect there to be 6 DOF +1 frequencies to be disrupting this signal (due to the physical nature of my ...
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0answers
23 views

Representing a Concept

From Formal Concept Analysis: If I have a set of objects: G={Shark, Penguin, Bat} and a set of attributes: M={Breathe Underwater, Can Fly, has Vertebrae} and I make a chart to represent my ...
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1answer
31 views

Using Excel to calculate relative difference between three numbers

Background I am trying to produce a table of values for the positioning of the hands of a clock at any time, limited by one second intervals, to demonstrate the feasibility of an ultra precise, ...
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1answer
28 views

Function to convert all -ve numbers into their +ve counterparts without affecting present +ve values (-12 to 12)

I am essentially after a function that will convert negative values in my Excel spreadsheet into their positive equivalents without affecting the present positive values. A sample of my data would ...
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0answers
28 views

Mathematical equivalent to curve fit between polynomials

I am adapting a calculation done in an Excel workbook to code. Right now, we are predicting a variable based on three other variables, say $x,y,z$. We are creating six functions of $x$ and $y$ at ...
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1answer
26 views

Interpreting Entropy

All you data scientists will probably know the entropy equation: $$H(p)=-\sum_{i=1}^{n}{{p}_{i}}\cdot\log_{2}{{p}_{i}}$$ And, using this, I was messing around with some compression, and calculated ...
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1answer
8 views

What measurement should be used to determine per unit capacity of a given volume ish question

I am reselling data packages and would like to add a sense of scale to the packages. Without disputing actual numbers, an email message is between (3-20)Kbytes, a photo 270kb, a web page ...
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0answers
10 views

Is it always possible to find a logistic regression model that yields zero training error on any dataset?

I am leaning towards no. A logit regression model is just one function, and there is no way its coefficients can accurately predict an entire dataset, outliers and all. Is this the correct intuition?
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2answers
51 views

How to verify how good my data is?

I'm in an undergrad physics lab right now and I have taken some data. The theoretical curve should be proportional to $\cos^2(\theta)$. How can I quantify how close my data values are to this ...
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0answers
12 views

When to use the various mean functions (arithmetic, geometric, quadratic) appropriately?

In data analysis, when are the use of these different means appropriate? For example, I'm using data to infer the peak of waveforms at different points around a semicircle. If my data has intensity ...
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0answers
7 views

Montonicity and Nonlinearity in data

I wish to find out why the following function $y_i=\sum_{l=1}^N\frac{ \theta_l}{1+ \exp-(\sum _j^M \theta_j x_ij +b_j ) }, i=1,\dots, P$ shows a linear, monotonic relationship instead of a ...
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0answers
32 views

Data analysis: How did people beat the Great Hall game?

This is the game: There is a Great Hall with 102 doors. 100 of these doors lead to one of 100 different side rooms. The 101st door, at the end of the Great Hall leads to the Great Tower, where ...
4
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2answers
58 views

Chaos theory and fractal geometry: Constructing from data

I understand that fractal geometry represents behaviour of 'chaotic' system, if I am not wrong. And also, fractals are generated by a recursive function. But, lets say I have random data lying with ...
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0answers
9 views

Accurate numerical integration for “data times an analytical function”

The Question is as follows: I have an algorithm/data that provides me the value of a function $f(x,y,z)$ on the points of a grid. On the other hand I have an analytical function ...
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0answers
35 views

Peak Picking in Spectrum Data (MS Excel)

I'm working often with spectral data of various gases, and the bulk of the data analysis is assigning the peaks with maximum signal (y-axis) to frequency (x-axis). Often we have several thousand data ...
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0answers
13 views

How does Link Analysis work?

Currently, I am into Link Analysis in data mining. I am kind of having a hard time to understand the Link Analysis. I have studied Association Rules and this is my next goal to understand. I have been ...
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0answers
36 views

How can I interpolate the following data and get the equation?

I want to interpolate between three vectors which have 8 rows in each. For eg. X = [1 2 3 4 5 6 7 8], Y = [7 8 9 10 11 12 13 14 ], Z = [15 16 17 18 19 20 21 22] I want to find the equation Z = ...
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0answers
20 views

What is the name (if any) of this statistical analysis concept?

I have a list of random numbers. I sort them, and designate each one as belonging to a tier of some sort (quartiles, percentiles, or even arbitrary cutoff points by proportion) based on the ...
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1answer
23 views

bias-variance trade off

Perhaps the most primitive (and yet very effective) way of estimating a density is by using a histogram. In a histogram, we can manage the 'precision' of the distribution by adjusting the number of ...
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0answers
7 views

Translating data query into Domain Relational Calculus

Given a following table named BOOKING, which contains three columns, guest_name, room_number and booking_date, how do I find the all the guest_name that have the same room_number and booking_date? I ...
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0answers
26 views

What function should I use to fit this data? Logistic function is not good enough fit.

I'm using curve_fit from numpy to try an fit some data I have. The function I used was the logistic function defined http://en.wikipedia.org/wiki/Logistic_function and the parameters I picked were ...
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0answers
16 views

Statistics, distributions and graphing

Lets say that you have data containing one variable - the waiting time between each car passing from 1200 hours... so you have something like 23, 54, 26, 8, 2, 59 etc what is the best way to analyse ...
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0answers
14 views

Determine the multi-dimensional relationship given the data

I have a dependent variable - A and 3 independent variables, H,V and N I have a data for all the variables and dependency relationship is based on my operational knowledge. I'd like to know what ...
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1answer
23 views

Application of wavelet analysis in computer science

I am doing research in computer science (data mining), do you think wavelet analysis is useful for me?
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0answers
22 views

How can I get the covariance just given the variance?

This is a fairly straight forward problem but I don't know how to calculate the covariance given just the variance of X and Y. Suppose X and Y are independent random variables such that Var(X)=1 and ...
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0answers
26 views

How to minimize the Kolmogorov-Smirnov statistic with Power-law distribution

I'm fitting data into a power-law distribution. In order to do this I need to solve two parameters: the scaling parameter $\alpha$ and the lower bound $x_{\min}$ In order for me to solve $\alpha $ I ...
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0answers
24 views

What is the related function between these point?

What is the related function between these point? $(1,5)(2,7.5)(3,8.75)(4,9.375)(5,9.688)(6,9.844)$ $y=ab^x$ does not relate?
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1answer
38 views

Linear Regression Application

I have a linear equation as follows: $B_0*x_0 + B_1*x_1 + ... + B_8*x_8 = result$ And i have about 200 different situations that are categorized into two different groups, depending on whether ...
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0answers
30 views

Noise Reduction

I'm working on a problem that involves production rate data from oil wells. These rates are recorded per month i.e. after a month of production the produced volume is calculated and reported as rate ...
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4answers
83 views

Why do graphs sometimes have unevenly spaced intervals in axis e.g. logarithmic

Why do some graphs not have evenly spaced out units on the x or y-axis? For example they have log on one or both of the axis? Here's an example from this page I guess the page does give a bit of an ...
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0answers
30 views

Is Principal Component Analysis applicable to this type of situation?

I'm trying to model the response of ant populations to pheromones in this way: The ants are simulated as Self Propelled Particles with internal energy. They undergo acceleration due to their internal ...
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0answers
18 views

Significant difference in a group of numbers

I have a series of results for groups of students achieving a certain level and I need to highlight where the results for different groups are significantly high or low. For example: Results show ...
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0answers
24 views

Method for measuring co-occurence

I have a dataset that lists a large number of binary variables for each member of the populations. It basically looks like this: ...
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0answers
28 views

Predictive models

Given a set of temperatures of different cities for a month, which prediction model should I use for a two day look ahead prediction? Regression models or Time series?
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1answer
19 views

rotating and exchanging x for y's in regression

I was just wondering what happens generally if i send all my x points to y's and y's to x's (i.e reflect along the y=x line) - if I change the x's and y's will my old error minimizing line still be ...
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0answers
19 views

Compress Unit ID Permutations

For my multiplayer RTS game, I need to send over the ID's of a player's units selected in a single integer. For every player, there are 16 units, each with an integer ID between 1-16 (inclusive), and ...
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1answer
27 views

$P(X > \mu + \sigma) > 0$?

I'm doing some data analysis. Let $X$ follow an unknown distribution, with a certain average $E[X]$ and a standard deviation $\sigma$. Both values are calculated using the (corrected) point ...
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2answers
64 views

How do I find the missing sample points with the Mean and Sample Standard Deviation?

I am completely lost on this statistics question: A statistician had a data set containing 13 data points written in his research notebook. He spilled coffee on his notebook and now he cannot read ...