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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+50

Unsupervised learning algorithms to detect anomaly in waves.

I have a sample of graphs (more than 10000...). that look like in the image below: I am searching for an unsupervised learning algorithms that can help me to detect anomalous observations. Here ...
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0answers
12 views

identify nature of missingness for categorical variables

could you please give me some hints for identifying the nature of missingness for categorical variables' missing value? I mean, I gave a fast search on google scholar but I didn't find anything ...
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0answers
12 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 ...
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0answers
92 views
1
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1answer
46 views

fastest and most efficent way to count all combinations in many sets and sum them together

I am a Java programmer who has reached the limits of brute computer power. My relational database (and non relational databases) is not producing results quick enough and I have hit a bottleneck in ...
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0answers
30 views

Reading Graphs to solve probability

Each point in the scatterplot above represents a person's systolic and diastolic blood presures. What fraction of the 24 people had either a systolic pressure over 140millimeters of mercury (mm Hg) ...
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0answers
9 views

PCA: what if continous variables are frequencies

I've got a data set that exists out of 5000 variables and 6000 instances. Each element of the data sets describes a frequency. It's a documentTermMatrix. Now I would like to do some data reduction, ...
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0answers
24 views

What are the best data structure implementations for each of Kruskal’s and Prim’s algorithms [closed]

What are the best data structure implementations for each of Kruskal’s and Prim’s algorithms?
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0answers
5 views

Hurst exponent for decay evaluation

i would like to evaluate rate of decay of tail of my histogram. Expressing histogram on loglog plot gives straight line in the range where i have gathered a lot of data. Unfortunately the line is ...
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0answers
12 views

Curve 'anti-correlation' detection

If I have a data set, what algorithm can I use to detect when one curve moves in clear opposition to the majority of curves? For example: At point 15, the purple line moves up in opposition to the ...
2
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1answer
21 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 ...
0
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0answers
15 views

Analyzing/Modeling DynamoDB Usage

I'm seeking the correct mathematical tools to analyze/model a real world process for the purpose of optimizing resource allocation. I want to analyze consumed throughput of a AWS DynamoDB table and ...
0
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1answer
54 views

Interpreting 3 Circled Venn Diagrams

The Venn diagram above represents the 20 students who took one or more of the 3 available art classes or took no art classes at all. two students took no classes at all. 1.How many people take only ...
0
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1answer
18 views

Chart Question and Percentages

The Venn Diagram above represents the 20 students who took one or more of the 3 available art class or took no art class at all. What percent of the students took only 1 art class? A. 10% B. 20% C. ...
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1answer
23 views

solving T(n) = 4T(n/2) + n^3 + n*(log(n))^2

I am trying to solve a recurrence by using substitution method. The recurrence relation is: $$T(n) = 4T\left(\frac n2\right) + n^3 + n\cdot\log^2 n$$ i tried to solve this also with master method... ...
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0answers
15 views

How can I find the value of the X-axis in the middle of the plateau shown on the chart?

On the chart below, I have 4 data sets. Each has plateau'ed at 50 on the Y-axis. I want to be able to mathematically calculate the value of the X-axis from the middle of the plateau (marked with a red ...
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0answers
22 views

Maximum Error Tolerances When Forecasting A Random Time Series

I have been working on an approach for forecasting random time series with a given maximum error tolerance for each forecasted point less than 10%-15% of the range of possible values. I have not been ...
2
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1answer
74 views

How to transform data distributed around zero to make it closer to normal?

I have data that ranges continuously from $-1$ to $+1$, with lots of zeros in the middle. I want to transform the data to a normal distribution. How would I do this? My normal approach with data ...
0
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0answers
10 views

Algorithm does not converge in R [migrated]

I am doing a logistic regression in R, where I am modeling how potholes and weather correlate to accidents. When I run a logistic regression, I get the message "Algorithm does not converge" The ...
0
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1answer
447 views

Comparing annualised volatility from monthly and annual data

I fear there is a very simple answer to this question and its killing me that I can't see it. I am interested in calculating historical volatility: I have monthly index values starting in Jan 2005 ...
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0answers
16 views

How can I apply inverse Abel Transform to a Data?

I have a data with X values and corresponding Y values. When I plot intensity map (2D histogram) of the data, I get a good image. I want to apply inverse Abel Transform to this image. How can I do it? ...
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0answers
7 views

Mean value of discrete periodic signals

It is clear that a continuous periodic signal always takes at some point $x_m$ the absolute mean value. Then we could define the absolute mean value of the signal as the value that it takes at $x_m$. ...
0
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0answers
12 views

Estimation by OLS vs FE

I am working in estimating an econometric model with panel data, and for some reason I get almost the same results using OLS and Fixed Effects, even though I am quite sure that that there omitted ...
1
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2answers
18 views

Finding simplest function to distinguish 2 sets

I wish to find a function that distinguishes $2$ sets. I have m data values in form of n-tuples out of which k are supposed to be mapped to a value less than $0$ and other m-k are supposed to be ...
2
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0answers
23 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 ...
0
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1answer
12 views

confusion in percentiles

in definition of percentile, it is said that, some value is in 30th percentile means, 30 percent of the data values are lower than the given value. But my confusion is, what if I have 1000 data ...
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2answers
218 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 ...
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2answers
97 views

Probability of name collision

Question on statistics & probability: I am trying to find the best way to build a unique key. Data i have: 1) first name 2) last name 3) DOB 4) gender So, assuming those are correct fields (not ...
2
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0answers
28 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 ...
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0answers
13 views

different data fitting methods

I have a list of 2-dimensional points and I want to know different techniques of arriving at an approximate analytic relation between y and x. Also important would be to understand how one technique ...
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0answers
26 views

Histogram Interpretation

For some reason my brain cannot comprehend this histogram. Is this normal or skewed? The main portion of the histogram looks like a normal distribution, but it is not placed in the center, and there ...
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2answers
171 views

Difference between Topological Data Analysis and Graph Technology

I'm trying to understand the difference between Oracle's graph technology, which apparently has an inherent understanding of topology, and Ayasdi's Topological Data Analysis technology. Are these two ...
0
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1answer
39 views

How to interpolate between sets of data

I'm probably using the wrong terminology, making it difficult to find a starting point. I have a set of motor data that looks like this: I can easily create a trend line for a given flow rate ...
0
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0answers
33 views

Minimum number of periods to determine periodicity

Is there a minimum window window length to determine true periodicity with a given estimated period. For example, if the same event is tested for every second and is observed twice at times 1 minute ...
0
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0answers
19 views

reducing data that are very close to one another

so, I have this problem. I have to do image analysis to get the boundary of an image. I perform image analysis to get a boundary representation of the object. The problem is, there is an overlap of ...
0
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0answers
18 views

Correlation method for speed measurement

I have data from two sensors on the road and I'd like to calculate the vehicle speed. The data are a bit noisy, so I was thinking about making a correlation of these data from two sensors with a ...
0
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1answer
13 views

Is Expectation Propagation (EP) affected by the prior?

I understand EP by reading Minka's thesis: http://research.microsoft.com/en-us/um/people/minka/papers/ep/minka-ep-uai.pdf I'm trying to apply it to solve a Bayesian inference problem. However, I'm ...
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1answer
54 views

Calculate 90th percentile of F distribution using “rchisq” function in R programming language

I am working on a problem for my Data Analysis class and I have to figure out a way to calculate the 90th percentile of the $F(3,5)$ distribution using the "rchisq" function in R(programming ...
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0answers
16 views

Find two clusters in an ordinated array

As the titles goes, I have an array of sorted real positive numbers, and some information on the structure of the data. I know that there are two constants $a>>b>0$ and two other numbers ...
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2answers
40 views

How to interpret the result of correlation between two discrete signals

Before starting, let me say I'm not a mathematician, I'm just a curious engineer, with a master's degree in engineering and computer science. I have been using this book The Scientist and Engineer's ...
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0answers
13 views

Does logged data have to be transformed back to its original form before testing the accuracy?

I have run my data through a model in r, i ran ARIMA to forecast. The model forces a log transformation to be applied to the data. To test the accuracy of the fitted model formed by ARIMA would i need ...
0
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0answers
11 views

Making a graph with information

I would like to ask what appropriate graph I should use and maybe an example to help me, I am struggling on what type of graph will be appropriate for this, and knowing could help me with the further ...
0
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0answers
23 views

Generalised chi square PDF: 2 normal DOF with different widths

I'm trying to derive the PDF $f_Z(x)$ for the random variable $Z = X^2 + Y^2$ where $X \sim N(0, \sigma_1)$ and $Y \sim N(0, \sigma_2)$. Searching here I've found this solution, which is only valid if ...
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1answer
32 views

Least squares fitting using cosine function?

Hello I am trying to fit a harmonic of the form $$y = b + c\cos(x)$$ to four data points (0,6.1) (.5,5.4) (1,3.9) (1.5,1.6) using least squares for homework. I know that the error $= Y_i - f(x_i)$ but ...
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1answer
14 views

What statistical analysis to use on a list of dates?

I suffer from migraines and for many years I've kept a log of each attack. I now want to do some analysis on the dates of each attack to see if there are any patterns. I intend to check the ...
5
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1answer
59 views

Queue and Stack in Computer Science and relation to MATH

For Creating a Queue Q we use two Stack S1,S2. for insert x in the end of Q we do Push(S1,x). for deleting element from front of Q, (if Q is not empty) we do Pop(S2). if on Q that at first is empty, ...
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0answers
41 views

Using significant figures, what would the answer be?

I've been learning about significant figures and I have a few questions. When you multiply/divide, the number of significant figures in the answer should be the same as the term with the least number ...
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0answers
11 views

Polynomial Data Fitting with Two Variables

I have the following data and I want to find the equation interpolating the given data. For example equation for given sample data is simple $a^2*b+10$ ...
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3answers
53 views

fit sine wave to data

I have some astronomical data which I know has a sinusoidal component to it of the form y = Asin(Ωt+Φ). The period of the sinusoid is equal to a sidereal day. So ...
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1answer
143 views

How do you set the range for ListPlot (mathematica)

I have a large set (about 2050 values) of data that I would like to make a graph out of. The data is in two columns in Excel. I copied the first column and made the list x={0, 3.6, 7.1, 10.7...} and ...