Questions tagged [curves]

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1answer
42 views

How to fit the flipped exponential-function in Excel? [closed]

I would like to know whether it is possible to fit the second graph below in Excel with an exponential fit? Unfortunately the "Exponential fit"-button is greyed out and I can't choose this ...
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0answers
24 views

Intuition behind Cumulative Accuracy Profile(CAP)

I am really having trouble understanding the intuition behind Cumulative Accuracy Profile(CAP) Curve. I mean where exactly does the CAP curve is used and how do you read the CAP curve? Parts of the ...
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0answers
47 views

In deep learning, can we interpret error = f(epoch count) as a learning curve?

I read about how to use learning curves to estimate a model's bias and variance, and see how much it overfits. The learning curve definition is "error as a function of the number of training samples",...
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25 views

modeling a electrical pulse which is technically time dependent

I have an electrical pulse that I need to fit a curve to a certain area of but not the entire thing. The whole pulse looks like this However the only part that I need to model is this My boss ...
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0answers
175 views

Adjusted Kaplan Meier in STATA : stcurve or sts graph adjustfor

I've been asked by a reviewer to plot an adjusted Kaplan Meier graph. I understood that with sts graph and adjustfor, the adjustment was to zero values of all the variables. So I tried to use stcurve,...
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0answers
66 views

KS-style test between curves in general

The setup of my problem is that I have some response variable, $Y$, and a predictor, $X$. I have measurements on both variables from two groups. In each group, there is one $Y$ per $X$. I want to ...
3
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1answer
91 views

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: ...
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0answers
53 views

Difference/comparison of two different sized sets of data

I have the data of two different devices (a and b) measuring the same outcome along the time. These results are approximate but have different values. I would like to assess the variation/agreement ...
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2answers
238 views

In elbow curve how to find the point from where the curve starts to rise? [closed]

I am computing a distance on my data. The result is then being sorted in ascending order. The samples having distance more than a specific threshold are to be marked as outliers and will be discarded. ...
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1answer
34 views

Should Learning Curves be Plotted only on Train or the Entire Dataset?

In order to compare a few models to start my ML project, first I split the dataset into train and test, and then performed nested CV on the training set only and got my fair estimate of true risk on ...
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0answers
236 views

What defines a plateau in a saturation curve?

I am working on a dynamic visual. To be more specific, it is a saturation curve (also known as accumulative/cumulative curve that reaches to a maximum of 100%. I am trying to define a variable that ...
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1answer
76 views

What method can I use to produce a single curve from a number of curves?

I am looking for a good method to combine a set of curves into a single curve. Those curves have been produced by performing a measurement/testing n-number of times under similar conditions. What I ...
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0answers
70 views

how to calculate curvature of multivariate function?

EDIT1: tried to clarify the question Context In the context of an MCMC investigation of non-linear interaction effects in dichotomous models, I am creating data generating processes based on the ...
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0answers
27 views

How to represent local significant differences between curves

I want to compare some curves to a 'normality corridor', and I would like to show in what regions (x values) the difference is significant.Take the example below, where I want to compare the dashed ...
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1answer
56 views

How to compare curves behavior?

I want to know how I can compare the "behavior of curves" and see what curves behave more similar. In the link below, in the 1st graph we have 4 curves through out time. http://www.sooty.ca/sooty/BDI....
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1answer
492 views

ROC curve:difference between FPR x TPR and false positives x true positives

Background I'm trying to understand ROC curves, however I sometimes read that you can simply go one up for a True positive (TP) and one to the right for a False positive (FP), as mentioned here: ...
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1answer
165 views

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 ...
2
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1answer
476 views

Choosing estimator based on Precision-Recall Curve

I hope you will help with this one. Below you see my Precision-Recall curves after performing 10-fold Stratified Cross Validation on my dataset. Note that my dataset is imbalanced that's why I'm ...
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1answer
1k views
1
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1answer
1k views

“Changing” standard deviation?

I will admit to being just a hair about a novice when it comes to stats, but I feel like I have a decent working knowledge of things such as normal distribution, linear curves, standard deviations, ...
4
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1answer
817 views

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 ...
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1answer
228 views

Logistic-regression probability score used for reordering rows for plotting ROC curve: is it the actual, positive, or negative class probability?

I want to draw my own ROC curve, such as explained in the accepted answer to this question: Understanding ROC curve However, it isn't clearly explained what the 'score' used represents. It is used ...
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1answer
1k views

ROC AUC and PR AUC: Are the AUC values different for each class?

When dealing with a binary classification problem, where the decision function threshold is being varied from 0 to 1 at step 0.1: When calculating the Area Under the Curve (AUC) for a ROC Curve plot (...
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1answer
43 views

Normal distribution curve percentages

Lets assume I’m grading following a normal distribution but instead of having a standard grading scale from A to F I have a grading scale from A to J with no plus or minus. Whats the percentage for ...
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1answer
121 views

Vertically translated depreciation curve: Update the exponential regression coefficient

I have an exponential regression equation that I use to predict the condition of roads. The equation can be found on page 53 of the original master's thesis: Development of a Flexible Framework for ...
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1answer
696 views

How to extend the dynamic time warping to 3D Cartesian space

I already searched the topics here but couldn't figure out clearly what to do so I'm asking here. I have thousands of fiber tracts (the outputs of a tractography algorithm on brain diffusion MRI) that ...
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2answers
2k views

Exponential regression trendline does not match data

I'm attempting to generate an exponential regression equation using Excel 2010. I plan to use the equation to predict the future condition of roads. I've mocked up a simple chart in Excel using the ...
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1answer
202 views

Clustering curves

I am trying to cluster gas wells based on their production behavior based on Gas/Water ratio vs cumulative water produced plots. Would appreciate suggestions to solve this problem.
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1answer
97 views

Road condition: Project future condition by appending part of a deterioration curve?

I inspect a road network's condition every three years: ...
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0answers
28 views

Constant Curve for Cumulative Binomial

I am simulating traffic flow and have come across a rather interesting statistics problem that I'm having trouble wrapping my head around. I am modeling a stretch of road comprised of 2 lanes. Lets ...
1
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1answer
200 views

Curve disaggregation with neural network

I have to extract a specific curve from an aggregate curve. An example is illustrated in the picture below, the blue curve is the aggregate curve, and I want to extract the red curve from the latter. ...
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0answers
155 views

Statistical test to use to compare EMG waveforms with only the mean and sd?

I have to compare processed EMG waveforms (smooth curves) that I recorded from 7 different leg muscles of 4 different subjects to reference EMG data (Winter book). The problem is that for the ...
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0answers
204 views

Comparing two (or more) curves

I'm rather new to R and statistics. I'm analyzing intonation curves (time, fundamental frequency), and I'm interested in comparing pitch curves of different speakers. I am particularly interested in ...
5
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1answer
465 views

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 ...
5
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1answer
2k views

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)....
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0answers
101 views

Measuring magnitude of variation between 2 one-phase association exponential curves

I am currently testing the independence of two unpaired conditions A and B; with each condition representing a set of 12 values (aka bins) that compose a one-phase association exponential curve. Each ...
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1answer
84 views

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 ...
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1answer
801 views

How to measure if data conforms to logarithmic curve

I am collecting data that should closely resembles a logarithmic curve. I have many datasets. How can I measure how closely each dataset resembles a logarithmic curve and call out any outlying ...
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1answer
31 views

Extracting values from a sigmoidal dose curve

I need to extract the real lethal doses from a sigmoidal dose curve from a probit model. The doses (mg) are the X-Axis and were log transformed. Model parameters were not reported, only that the true ...
3
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2answers
837 views

Average curve from set of curves

I have done some initial analyses on some patient datasets regarding neuro-degenerative diseases. A method I've used is DFA (Detrended Fluctuation Analysis) in MATLAB, which produced a family of ...
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0answers
1k views

Why is the “training score” I get from the learning curve of Multinomial Naive Bayes so different from the training score of the Bernoulli version?

I'm comparing the learning curves of Bernoulli and Multinomial Naive Bayes using the 20_newsgroups dataset from scikit-learn for text-classification. I considered both the "training score" and the "...
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2answers
242 views

Describe a curve by other than formula, fitting or interpolation

I have a curve defined by a set of $(x,y)$ given points. After ploting these points I get : My aim is to study the sensitivity of the operation that results these points. In order to do that, the ...
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1answer
38 views

Name of type of curve that uses x value as a divisor for y

What is (or is there) a name of a curve that is on X and Y axis, where the Y value is divided by X? For example, Y at X being 1 = 100, Y at 2 = 100/2 Y at 3 = 100/3. The type of curve I am thinking ...
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3answers
12k views

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 ...
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647 views

Fitting the differences between two curves [closed]

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, ...
1
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1answer
793 views

find a general formula between two parameters using curve-fit

I am trying to study the relationship between two parameters say A and B for an image. For a single scene S1, I take 20 images ...
4
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1answer
56 views

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 ...
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1answer
187 views

Comparison method for curves using percentiles

I have a question regarding the use of quantiles for determining the enveloppe of a curve. This is what I am doing: I have a continuous variable ("var") that I turned discrete using cut ("var_cut"), ...
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0answers
1k views

Statistical comparison between two curves

I have two time course experiments of the same study, and I want to determine if the time course curve is statistically significant or not. Let's say I treated a group of people with drug A, measure ...
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1answer
2k views

Curvilinear relationship with moderator

I am trying to moderate a curve and determine which equation I should follow. A simple curvilinear relationship has the following equation: (1) $Y = b_0 + b_1X + b_2X^2$ (i.e. a linear term and a ...