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.

learn more… | top users | synonyms

2
votes
3answers
157 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
votes
2answers
764 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
votes
1answer
27 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 ...
0
votes
0answers
31 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 ...
0
votes
1answer
257 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, ...
0
votes
1answer
44 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 ...
0
votes
1answer
73 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 ...
0
votes
1answer
23 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 ...
0
votes
0answers
14 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?
1
vote
2answers
96 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 ...
1
vote
0answers
17 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 ...
0
votes
0answers
12 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 ...
1
vote
0answers
38 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 ...
5
votes
2answers
129 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 ...
0
votes
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 ...
0
votes
0answers
269 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 ...
0
votes
0answers
37 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 ...
1
vote
0answers
87 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 = ...
1
vote
0answers
26 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 ...
0
votes
1answer
38 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 ...
0
votes
0answers
9 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 ...
1
vote
0answers
39 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 ...
0
votes
0answers
17 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 ...
0
votes
0answers
18 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 ...
0
votes
1answer
65 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?
0
votes
0answers
135 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 ...
0
votes
0answers
51 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 ...
0
votes
0answers
51 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?
0
votes
1answer
57 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 ...
1
vote
0answers
40 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 ...
1
vote
4answers
302 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 ...
1
vote
0answers
46 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 ...
0
votes
0answers
40 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 ...
0
votes
0answers
25 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: ...
1
vote
0answers
30 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?
0
votes
1answer
25 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 ...
0
votes
0answers
27 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 ...
1
vote
1answer
69 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 ...
1
vote
2answers
459 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 ...
3
votes
2answers
144 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 ...
1
vote
0answers
178 views

Are there any programs like family echo that I can use to map mathematics?

Family echo is an online program that allows one to make a family tree, if nothing is clicked it shows most of the family tree as it is, but if one clicks a name one can see clearly all the ancestors ...
0
votes
1answer
59 views

There are 2 red, 3 pink, 4 orange, and 5 yellow jelly beans in the pocket. how many different ways can you choose at least one jelly bean?

Thanks a lot!There are 2 red, 3 pink, 4 orange, and 5 yellow jelly beans in the pocket. how many different ways can you choose at least one jelly bean?
0
votes
2answers
61 views

What property of $n$ does this test?

I have the following sample data: 1 true 3 false 12 false 10 true 7 true 9 false 8 false My question is, what property of ...
1
vote
1answer
21 views

Detecting periodic patterns in data - how often are the meetings held?

Suppose some people I know frequently have meetings, and suppose I want to find out whether there's a pattern to when these meetings take place, and if so how often they occur. I can take note of the ...
0
votes
0answers
36 views

What is the relationship between the Fourier spectrum and the information content?

Suppose you look at the Fourier transform of some data (say, a blurred image). The amount of high frequency signal tells you how much texture there is in the data (e.g., a blurrier image has a more ...
1
vote
0answers
87 views

How can non-binary data be tested for distinguishability from random?

Given a large string of Base-N digits (in other words, not necessarily binary), is there software or an algorithm that can output whether the data is reasonably pseudorandom or reveals a pattern? In ...
0
votes
1answer
35 views

comparing empirical data to a model prediction using exponents

I am not a mathematician, but I have a basic question about comparing numbers with exponents near $1$. I am evaluating how well a "model" works and I want to make a compelling case. For example, my ...
2
votes
1answer
44 views

Predicting the increase/decrease of number

I have these entries in my database that looks like this: ...
2
votes
0answers
46 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 ...
1
vote
0answers
16 views

Statistics linear modelling in R

Suppose I have a date set of the form: Test Subject/Sex/No. of mistakes made in the morning/ No. of mistakes made in the afternoon A / M / 2 / 5 B / F / 1 / 4 C / M / 3 / 5 D / F / 1 / 5 Suppose ...