Tagged Questions

Functional Data Analysis defines a framework where the fundamental units of analysis are functions.

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Study brain functional connectivity after ICA

I am new to neuralimaging, one thing that confuses me is the justification of computing correlation of those independent component network (ICN) from ICA. All papers I have read treat each independent ...
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21 views

Most efficient vector construction for Dynamic Time Warping

I'm in the process of folding FastDTW into my SVM and the question now is how to best format my data (irrespective of normalization). Here's an example of what I'm attempting to do - given two 3d ...
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1answer
43 views

Different number of time-points in functional data analysis

I have a data set that I wish to analyze using functional data analysis methods. Data consists of repeated measures of some characteristic on a number of inviduals. I have the time of the measurements ...
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2answers
69 views

Limiting joint distribution of estimators; Functional Statistics; Influence curves;

Let $X_1,...,X_n$ iid r.v. with distribution F, with mean $\mu$ and median $\theta$.Assume that $Var(X_i)=\sigma^2$ and $F'(\theta)>0$. If $\hat{\mu}_n$ is the sample mean, and $\hat{\theta}_n$ the ...
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1answer
24 views

Alternatives to absolute error?

Let me explain my scenario in which I need to calculate absolute error. Lets say the X is the actual value. And X' is the value of X with some error 'e'. So X' = X + e'. Lets say i = 1 to 10000. I ...
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1answer
72 views

Create a function from a data set when there is one independent variable and 3 dependent

I have a data set which consists of 1.Number of users, 2.Cpu usage, 3.Ram Usage, 4.Response time, The way I understand it Number of users is my independent variable. Is there a way, a method, or a ...
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0answers
26 views

Longitudinal data using functional principal components mixed effect models

I have collected speech perception performance in children during one-year followed-up (four time points). A battery of speech perception measures (i.e., five measures) were used at each test ...
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1answer
163 views

What are the differences between two kinds of PCA?

The book "Elements of Statistical Learning" describes Principal Components Analysis through SVD as follows: $ X = UDV^T $ Then $ UD $ are the Principal Components and $ V $ are the directions. ...
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1answer
64 views

Forecasting of density function

I am doing some research about forecasting time series of probability density functions. We are aiming to forecast a PDF given historically observed (usually, estimated) PDF. The forecasting method we ...
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0answers
44 views

PCA with same cases in different periods of time

I am new user of principal component analysis (PCA) and I have a big doubt. I have 32 observations with 45 variables and I know that I cannot use the simple PCA for this analysis (n < p). However, ...
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0answers
133 views

Rubric for good data analysis

As statistics education moves online, educators are facing new problems related to the administration of their courses. Jeff Leek and Roger Peng, for example, taught approximately 100,000 students ...
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1answer
1k views

Dynamic Time Warping and normalization

I'm using Dynamic Time Warping to match a "query" and a "template" curve and having reasonable success thus far, but I have some basic questions: I'm assessing a "match" by assessing whether the DTW ...
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1answer
88 views

Estimate global mean and stdev from samples taken at regular intervals

I have data from a load test of an automated system with several thousand data points that cover roughly 1 week of operation. I need to compare several algorithms for this system to see which is ...
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2answers
171 views

Data analysis on multiuser environment

I have following environment that I'd like to analyze. My company is divided in two teams: Insert Team (composed by 150 persons) Quality Check Team (composed by 10 persons) Suppose that all ...
2
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1answer
243 views

Modelling longitudinal data

We have longitudinal data on children(n<20) in which we measure different quantities A,B,C,D (like distance walked, time spent in school etc.). These are all continuous variables. We measure these ...
2
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0answers
191 views

What statistics to use when the data are polynomial functions (aka change over time)?

EDIT: OK, having spent the last couple of hours checking out some pubs on functional data analysis, I am actually starting to feel a little silly having asked the question in the first place! It's ...
9
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2answers
887 views

How to simulate functional data?

I'm trying to test various functional data analysis approaches. Ideally, i'd like to test the panel of approaches i have on simulated functional data. I've tried to generate simulated FD using an ...
2
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1answer
306 views

What is the level of measurement of image data?

Question: This is a bit of an abstract question, but bear with me. I am averaging images, to try and deduce what the average image of a specific subject looks like (just out of curiosity, it might ...
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0answers
232 views

Predicting curve registration parameters in functional data analysis with noisy data

I have some data I'm studying where functional data analysis seems like a promising approach. But having never tackled FDA before, I'm having trouble wrapping my head around it. For background, I ...
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1answer
825 views

Predicting response from new curves using fda package in R

Basically all I want to do is predict a scalar response using some curves. I've got as far as doing a regression (using fRegress from the fda package) but have no idea how to apply the results to a ...
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1answer
162 views

Variability of a curve with 4 parameters

Say I have 10,000 data in 2-D and I want to fit a curve to them. There are many functional forms this curve could take -- polynomial, B-spline, trigonometric, and so on. I've decided that I only want ...
5
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1answer
207 views

Estimating speed from position updates with uncertain time intervals

I have 2 alternative methods to solve a problem, and I was just wondering what people who know the math better than I think, and if there is a better method to use for this type of problem. The ...