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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11
votes
4answers
2k views

Mathematics base for data mining and artificial intelligence algorithms. [closed]

Could you give me some clarification about data mining and artificial intelligence algorithms? What mathematics base they used for? Could you give me starting point, in mathematics, to understand ...
10
votes
4answers
3k 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 ...
9
votes
3answers
481 views

Removing noise when the signal is not smooth

Suppose we have (an interval of) a time series of measurements: We assume it can be explained as a "simple" underlying signal overlaid by noise. I'm interested in finding a good algorithm to ...
5
votes
2answers
143 views

Highest points in heart cycle graph

I'm making an application that reads the heart cycle from a device, and I've aimed to get this image: Now, I need to get the highest points that appear in every cycle in order to calculate the ...
5
votes
2answers
485 views

Where to start learning about topological data analysis

I was wondering if anyone could help me out with finding a nice introductory introductory text for topological data analysis (I'm speaking as somebody who has two semesters of experience with ...
5
votes
1answer
680 views

Abstract Algebra for Business Intelligence / Data Mining

Twitter released its Algebird library, an abstract algebra library for scala. At a high level, what are the maths involved in abstract algebra that have an impact on aggregating large datasets?
4
votes
2answers
556 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 ...
4
votes
2answers
10k views

Value range of normalization methods? min-max, z-score, decimal scaling

I am working my way through Normalization (data transformation) of data and was curious about four methods: min-max normalization, 2. z-score, 3. z-score mean absolute deviation, and 4. decimal ...
4
votes
2answers
57 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 ...
4
votes
2answers
180 views

Detecting increasing pulse trains

I have a one dimensional point process representing the times of events which is also mixed in with lots of data that I regard as noise. The interval between the events in the point process are ...
3
votes
3answers
419 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? ...
3
votes
2answers
125 views

How do I use specific data points on a graph to determine an equation?

I need to find a function $f(x)$ such that the following data points would fit on it: $$f(1) = 0 \\ f(2) = 0.5 \\ f(4) = 1.0 \\ f(8) = 1.5 \\ \cdots $$ and so on. So the pattern is every time $x$ ...
3
votes
2answers
36 views

Power set of a set containing a set

I need some help understanding this concept a little better. I understand the general power sets, but only worked nice and easy examples where only the set consisted of only single elements like ...
3
votes
2answers
64 views

Need to find function by the data

I have found interesting sequence, but I can't find its function. Here are the input and output data: ...
3
votes
3answers
188 views

Testing for chaos in data

I have data for 3 variables ,each with respect to the discrete time values. How do I check for the existence of chaos for this 3D discrete system?(I don't have the analytic eqs.,just the data). MY ...
3
votes
1answer
227 views

Fitting a surface to 2D measurements

I am looking for a way to fit a surface given a set of measured data $(x, y) \mapsto z$. A typical example would consist of anywhere between $10$ and $30$ measurements spread evenly over a disc. ...
3
votes
1answer
153 views

Sigmoid function with separate control of derivative at 0 and sharpness of bend.

For a physical relationship, $f(x)$, I'm trying to model, i have a fairly good determination of some of the boundaries, such that $ f(0) = 0$ $f'(0) = B$ $ \lim_{x\to\infty} f = A $ So far, what I ...
3
votes
1answer
57 views

The number of nuts in a package of “Premium Cashews” is normally distributed with a mean of 433 and a standard deviation of 6 nuts.

The number of nuts in a package of "Premium Cashews" is normally distributed with a mean of 433 and a standard deviation of 6 nuts. Packages with fewer than 420 nuts or more than 445 nuts will be ...
3
votes
1answer
498 views

How do I 'reverse engineer' the standard deviation?

My problem is fairly concrete and direct. My company loves to do major business decisions based on many reports available on the media. These reports relates how our products are fairing in ...
3
votes
1answer
21 views

Where can I find a longitudinal study with a binary response?

I've spent the last couple of months trying to find real data (not simulated) of a longitudinal study, but I can't seem to find one. Any topic and time frame is fine, but the dependent variable must ...
3
votes
1answer
238 views

Lloyd's algorithm in normed vector spaces

How do I run Lloyd's algorithm in a normed vector space? The space: L*a*b* color space, finite sRGB segment, $R^3$ The distance metric: CIE94 using L*C*h* information derived from the L*a*b* ...
3
votes
0answers
169 views

How does 2D kriging interpolation work?

I have a grid of points Example ...
3
votes
1answer
170 views

Logistic functions - how to find the growth rate

We have the formule for a model with logistic growth: $$ N_t = N_{t-1} + g\, N_{t-1}\left( 1 -\dfrac{N_{t-1}}{K}\right)$$ where $g$ defines the growth rate and $K$ is the carrying capacity. Let's ...
2
votes
2answers
61 views

Converting data to a specified range

I am trying to convert data to a particular range of 0-10. Actual Data may vary from - 50000 - 26214400. I have broken this down in to 4 parts as follows - ...
2
votes
3answers
93 views

$4\log_2(n)=n$ How to Solve for $n$?

As the title suggests, my log skills are pretty lacking. Need to learn how to get from $4\log_2(n)=n$ to $n=16$ ($\log$ base $2$). I've searched Google and it seems I am missing some core concept ...
2
votes
1answer
393 views

Is there a scientific way to assign weights to historical data?

This is a common question I usually face while processing historical data. I have year on year data of an event for the past N years.I would like to assign weights to the data of these N years so that ...
2
votes
1answer
125 views

Find data to perform regression analysis

I'm trying to find some data (two continuous variables that I believe are correlated) online for which I can perform a regression anaylsis, my assignment sheet says: The data may be found anywhere ...
2
votes
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 ...
2
votes
2answers
168 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 ...
2
votes
1answer
8k 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 ...
2
votes
2answers
62 views

Finding similarity between elements using statistics

I have a dataset of DJs in which I'm trying to find DJs similar to a specific DJ. Each DJ has a set of a genres with a certain percentage. How can I find the similarity between 2 DJs? The following is ...
2
votes
1answer
28 views

Data Analysis and Probability

Two dice with a difference ... They appear identical, but one die is fair and the other is loaded so that the probability of throwing a 6 is 0.25. Bev picks a die at random and throws it, and it shows ...
2
votes
1answer
88 views

How to appropriately normalize financial data?

I am evaluating a normalization of financial data. Two colleagues feel certain of a certain approach, and I am befuddled. The approach shapes the results how they want (i.e., brings possibly extreme ...
2
votes
1answer
30 views

Continuity correction: Change P(2 ≤ x < 9) to continuous?

Convert discrete probability into continuous probability using continuous correction: attempt: Discrete: P(2 ≤ x < 9) therefore continuous should be Continuous: P(1.5 < X < 8.5) Is this ...
2
votes
1answer
52 views

Optimize database indexes, the sequel

Background For those not familiar with databases. Indices help to speed up database searches, but they come at the cost of memory. Since you like your database to be fast, they are best cached in RAM ...
2
votes
1answer
780 views

Mutual Information for clustering

I'm working on a document clustering application and decided to use Normalized Mutual Information as one of the measures of effectivenes. But I don't really understand how to implement this in that ...
2
votes
1answer
180 views

Techniques to find regression parameters for multiple datasets where a subset of parameters should be the same for all datasets

I have five sets of observations of measured y as some function of measured $x_1, x_2, x_3,\ldots$ and I want to fit five functions to these observations. They have the form $$ y = f(x_1, x_2, ...
2
votes
1answer
512 views

Data Type Classification in Statistics

It is my understanding that in statistics one has 4 basic data types: nominal, ordinal, ratio, and interval. I see cases where people refer to "count data" (which is a random variable whose range is ...
2
votes
1answer
95 views

What's the best function to use to fit this data?

{7502, 6610, 4988, 2861, 2242, 1746, 1433, 1312, 949, 793, 767, 664, 660, 653, 588, 578, 575, 572, 553, 500, 445, 418, 374, 165, 108} I was looking at the number of seeds for torrent files for ...
2
votes
1answer
2k views

Standard Deviation vs Standard Error

I am confused about the difference between standard deviation and error. When do I use which? From my lecture: Standard deviation quantifies spread of data about mean Standard error measures spread ...
2
votes
2answers
172 views

Working out the “best” score based on quantity and ratio

I'm not an expert with mathematics so I hope I'm posting in the right place! I've got a lot of products which can be rated good, bad and OK by a user. What I'm having trouble with is finding which is ...
2
votes
1answer
420 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
3answers
43 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 ...
2
votes
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 ...
2
votes
1answer
37 views

Predicting the increase/decrease of number

I have these entries in my database that looks like this: ...
2
votes
0answers
39 views

How can I infer order from partially ordered discrete sequences?

A really interesting problem that I can't stop thinking about! Have run in to this a couple of times but yet to find a smart approach to either solve or frame this problem. This is my try at ...
2
votes
1answer
64 views

Entropy determination regarding lossless data compression

Suppose I had many computer data files to compress losslessly and wanted to know what is the theoretical limit to each one as far as minimum filesize possible. How would a math person go about doing ...
2
votes
0answers
43 views

How can I minimize the error from fitting two functions to different parts of data?

I have some data, and I expect that part of the data will fit to a power law, and part of the data to a line. Here's a made up example of some similar data: Where I've made the red part a quadratic ...
2
votes
0answers
53 views

Predicting profit with price variation

I am currently working on a high school project that aims to predict profit from X amount of items to Y amount of profit based off a deviated sale price. For instance: I sale 10 cookies for 10 ...
2
votes
0answers
42 views

Find spikes in data

I have some datasets and I need to find spikes in them. Imagine the data looks like trading data. If the spike is big enough, I need to log it, otherwise, proceed in the analysis. I tried with a ...