Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [curves]

76 questions
22
votes
5 answers

Similarity measures between curves?

I would like to compute the measure of similarity between two ordered sets of points---the ones under User compared with the ones under Teacher: The points are curves in 3D space, but I was thinking that the problem is simplified if I plotted them…
Alex
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2 answers

Checking for a statistically significant peak

I have a set of data, $y$ and $x$. I would like to test the following hypothesis: There is a peak in $y$; that is as $x$ increases, $y$ first increases and then decreases. My first idea was fitting $x$ and $x^2$ in a SLR. That is, if I find that the…
Nikita Samoylov
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12
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1 answer

How to form a Precision-Recall curve when I only have one value for P-R?

I have a data mining assignment where I make a content-based image retrieval system. I have 20 images of 5 animals. So in total 100 images. My system returns the 10 most relevant images to an input image. Now I need to evaluate the performance of my…
jeff
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9
votes
1 answer

Shape detection for time series data

I have a large collection of time series - measurements taken every 15 minutes (96 measurements in a day) over the span of 1 year at various different locations. I've broken up each time series into 365 separate smaller time series, 1 for each day…
JCWong
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7
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1 answer

Does it take progressively fewer EXTRA correct answers to move up a grading curve in standardised exams?

A previous year's grading curve for an exam I will be sitting is : Assuming the exam has 100 (or any number of) questions each equally weighted, will it take fewer extra correct answers to move up percentiles as you move away from the average? E.g.…
K-Feldspar
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7
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0 answers

Fitting the differences between two curves

The problem I'm trying to solve is to algorithmically figure out whether two curves converge or diverge in a graph (visually the problem is almost trivial). For examples: The left one is convergence, and the right is divergence. Note that the in…
skyork
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7
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2 answers

Fit between two curves

I am trying to determine the fit between two curves (example shown below). Both curves are plotted here as a bunch of XY data points (not functions). The curves represent the trajectories of two planes taxiing, and I'm trying to figure out how far…
Jeff
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5
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1 answer

Getting ROC curve from markov chain in r

I've been working on some attribution modeling in R, following the markov chain-based methodology described here. In order to compare the sensitivity and specificity trade-offs of using models of different markov orders, I'd like to look at a ROC…
babyseal
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5
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1 answer

The issue of quantile curves crossing each other

While trying to perform some quantile regressions on some data I have encountered a classic problem: the 0.25,0.50, 0.75, 0.95 quantile curves are crossing each other (I am dealing with linear curves). I am currently working with Stata using the…
Statlearner
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4
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0 answers

Test for statistical difference between two curves on same plot?

I've got data plotted for A/Ci curves (plant physiology, A=photosynthesis rate, Ci=internal CO2 concentration--essentially it's a dose-response relationship). Generally, when this type of data is presented, people just add SE error bars (like the…
Jas Max
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4
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1 answer

ROC curve: small focused sample vs large sample

Background I'm currently reading the book Data ming: practical machine learning tools and techniques and came across the following ROC curve: The text corresponding to this figure: Method A excels if a small, focused sample is sought; that…
KingBoomie
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4
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1 answer

How can Precision-Recall (PR) curves be used to judge overall classifier performance when Precision and Recall are class based metrics?

How can Precision-Recall (PR) curves be used to judge overall classifier performance when Precision and Recall are class based metrics? Since in a binary classifier, there are two classes, often labelled positive (+1) and negative (-1). Yet, the…
Aalawlx
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4
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3 answers

In statistical terminology, what is the opposite of "peak"?

When we see a curve (or a normal distribution), we describe the highest value as "peak". Let's imagine we have a curve with only a minimum value (like an inverted hat), what do we call that minimum value?
RockTheStar
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1 answer

How do I detect the "corner" in a set of data as it arrives?

Apologies from the start if my terminology is inaccurate, but what I have is a series of measurements that are made over a short time period from a hardware device to which I have just supplied a stimulus. The measurements fairly quickly settle…
Roger Rowland
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3
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1 answer

Standardize by min, max, and arbitrary chosen middle to range from -1 through 0 in the middle to +1 in max

How to standardize data by the following example: +---------------+-------+--------+ | comments | input | output | +---------------+-------+--------+ | min | 1 | -1 | | chosen middle | 2 | 0 | | | 3…
Przemyslaw Remin
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