Questions tagged [bimodal]

A bimodal distribution is a probability distribution with two different modes. These appear as distinct peaks (local maxima) in the probability density function for continuous distributions and the probability mass function for discrete distributions..

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Recovering Bimodal distribution parameters using pymc3

I am trying to determine the parameters mu1, mu2, sigma1, sigma2, and w of a bimodal distribution using pymc3. x ~ w * Norm(u1, sigma1) + (1-w) * Norm(u1, sigma2) I use the following code: ...
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How is a Bimodal distribution platykurtic?

I am trying to understand how the distribution on the right is platykurtic? I learned that platykurtic indicates lighter and thinner tails and from what it looks like, the bimodal distribution, with a ...
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Statistic for measuring the magnitude of bimodality in a distribution?

Here are some distributions of US political views by industry: After observing their mostly bimodal nature, I would like to measure the degree of bimodality in each of the distributions for the ...
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89 views

Difficulty splitting bimodal data

I'm working with a bimodal data set and need to split this bimodal data to 1) estimate the proportion of data points in each distribution and 2) the mean of each distribution. I have approached this a ...
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30 views

Sum of Bimodal Distributions? [closed]

If I'm trying to estimate a the sum of a bunch of random variables, where each random variable is a bimodal distribution, how would i go about thinking or modeling what that looks like?
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What is a reasonable method for two sample test on cut-off measurements?

This is a question regarding biostatistics. I am digging into some statistical analysis with SingleCellSignalR, which is a tool to predict cellular interaction with single-cell RNA-seq data. I was ...
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25 views

What distribution does this data take?

I have several unique ID's that have this distribution, but I cannot find any information on the type. I'm leaning on this being a bimodal distribution, but am not sure. I need to fit these to a ...
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7 views

Does the sampling distribution for the median of a bimodal distribution depend on sample size? [duplicate]

I have a dataset of project sizes (in $) which is sometimes bimodal, sometimes not (it varies across time and I am using annual data sets). These projects are distributed across two types of project ...
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1answer
26 views

Can I do a hypothesis test to see if two populations are different if there are known subpopulations within the data?

I have a continuously variable output (diffusivities) that I have measured from two different populations (say "Case 1" and "Case 2"), and I am trying to see if the two populations ...
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1answer
981 views

How to apply a statistical test on either a bi-modal distribution OR how to transform it to parametric?

I have lifetimevalue (LTV) data for 3 groups in my set. For each group, their respective LTV looks bi-modal. I need to test if there is a statistical significance between those groups with respect to ...
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313 views

Normalizing a strongly bimodal distribution

I am working with measurements of "spring vigor" of a perennial plant measured on a 0-20 scale. It is meant to screen for winter damage. In this experiment, there are many individuals who are ...
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1answer
53 views

difference between binormal and bimodal?

I am trying to simulate in R a normal distribution with two different means, and I wrote: ...
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194 views

Data transformation : bimodal feature

I have a data feature that follows closely a bimodal distribution (mixture of two separate normal distributions with different mean, standard deviation and weights). Is it meaningful to transform that ...
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testing whether data comes from a bi-modal distribution (python) [duplicate]

I have a variable which seems to be a mix of two Gaussian distributions (it is bi-modal with each mode looking normally distributed). I would like to identify anomalous samples. So my idea is to ...
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453 views

Comparing 2 mixture models using mixtools

I have 2 mixture models I'd like to compare. Specifically, I want to compare lamda (i.e. proportion/area under each distribution) as it looks like there are differences there. Is this possible? ...
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3k views

Splitting of bimodal distribution, use in regression models

I have a bimodal length-frequency distribution for the females of a species with a one-year life span. This pattern is not observed in the males. I suspect that the bimodality is due to different ...
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1answer
982 views

Can we model a bimodal response variable using a mixed effect model?

I have a response variable that is bimodal (basically, 2 normal distributions that are sticked together) and want to model it using a linear mixed effect model. Here is a quick example (in R): <...
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1answer
352 views

Is it appropriate to use the mean of the distinct u̶n̶i̶q̶u̶e̶ values from a bimodal distribution to split the data?

I have sets of data with a bimodal distribution and the best estimate of splitting the two seems to use the single (unique) values that can be taken, and calculate the mean. This mean value nicely ...
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Why is a mixture of two normally distributed variables only bimodal if their means differ by at least two times the common standard deviation?

Under mixture of two normal distributions: https://en.wikipedia.org/wiki/Multimodal_distribution#Mixture_of_two_normal_distributions "A mixture of two normal distributions has five parameters to ...
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How to find groups inside the dataset (test for bi-multimodality)

I have non-normally distributed dataset, a record of a parameter, e. g. 50 subjects reacted to stimulation, (9 periods of time in total). So I have a matrix of 50x9 numbers, 9 medians for each time-...
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1answer
59 views

How to sample/fit distribution from/for bi-modal data [closed]

The context is: I have a sequence of data, of which the histograms show a bi-modal pattern. My final goal is to sample from this sequence in a simulation project. Now we want to fit a parametric model ...
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442 views

Causes of bimodal distributions when bootstrapping a meta-analysis model

I help a colleague to bootstrap a meta-analysis mixed-effects model using the metafor R package framework authored by @Wolfgang. Interestingly and worryingly, for one of the model's coefficients I ...
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Theoretical reason for 1 linear model not being able to model a bimodal distribution?

Recently, I got a set of data where I try to predict the label (a continuous variable between 1000 - 3500) given 13 feature variables. By applying the kernel density approximation on the label (shown ...
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2answers
353 views

How to engineer a bimodal continuous feature for use in Decision Tree?

I have a predictor that exhibits "bimodal" behaviour. How can I engineer this feature to improve performance within a Decision Tree? For an intuitive example, consider how a binary flag of "moves ...
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771 views

How do I Identify a cutoff value from bimodal data?

I am putting together a regression model with data of carseat sales from the ISLR dataset. It is sales as a function of the independent variables. One of the variables has a bimodal distribution I ...
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1answer
5k views

How do I normalize a bimodal distribution?

I'm working with the Iris dataset. One of the variables, PetalWidth, has a clear bimodal distribution. My understanding is that multivariate regression sssumes ...
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1answer
574 views

Can I perform KMeans on a bimodal data?

I am preparing a dataset for KMean clusters. But a series of data appears to be bimodal: My question is: Can I perform KMeans on a bimodal data? If not, what kind ...
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1answer
63 views

Testing for difference in means with bimodally distributed data?

I have two bimodal distributions of data with two peaks (one around 0 and the other around 1). I have provided an example of one of the distributions. Although their means and variances are different,...
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1answer
1k views

Dependent variable - bimodal?

I have a dependent variable, days.to.event, that looks almost bimodal at 0 and 30. I understand that there is no transformation that can normalize this. In fact, when I fit a linear model (lm) with ...
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41 views

One dataset, two populations?

Setting: I have a single dataset from a simulation that appears to demonstrate bimodality. The dataset is composed of N measurements calculated at n different times and is two dimensional (N by n). At ...
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5k views

Simulating a bimodal distribution in the range of [1;5] in R

I want to simulate a continuous data set/variable with lower/upper bounds of [1;5], while at the same time ensure that the drawn distribution can be considered as bimodal. Searching for my problem, I ...
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2answers
1k views

Choosing center of histogram bins for fitting

I have a bimodal distribution, and if plotted with Mathematica it looks like this: Now, the lowest value from the actual data is 8196 and 690720, but as seen in the plot, Mathematica lets the data ...
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Multimodality of mixtures of more than two Normal distributions

Let $$\phi(x;\mu,\sigma) = \frac{1}{\sigma \sqrt{2\pi}} \exp \left(- \frac{(x-\mu)^2}{2\sigma^2}\right)$$ denote the Gaussian density function ($\sigma > 0$). Let $$f(x) = \sum_{i=1}^N p_i \...
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287 views

Bimodal distribution dispersion

what is the correct way to study the variability of a data set when all the observations are distributed like a bimodal distribution? For instance, here I identified the two modes as central index. ...
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1answer
2k views

Is this distribution bimodal? [duplicate]

so understanding what unimodal, bimodal & multimodal distributions mean was easy, but I wonder how strict should I be when I am applying the definitions to real data, in that sense, I need to ask, ...
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1answer
108 views

How to statistically distinguish between two types of time series (bimodal vs. not bimodal)?

I have two different types of time series. The first group of series is much more bimodal, and the second group is much flatter. For a given time series, I want to test whether it more likely belongs ...
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582 views

Bimodal posterior distribution

Do you know in which situations is it possible to have a bimodal posterior distribution for some parameters? I couldn't find any information on the web. Thanks for your help.
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1answer
180 views

Modeling bimodal time-to-event

Here is a plot of death registration frequencies by age for the UK in 1974. I see distributions like this quite often: there is some event (e.g. death) which happens either close to birth, or ...
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1answer
102 views

Bimodal MaxEnt distributions?

What kind of constrains give rise to bimodal distributions in the Maximum Entropy formalism? Are there any known results in this topic?
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51 views

Observing seasonality in a time series

I've got a time series which plots surface reflectance over time. Ideally surface reflectance is high in the winter and is low in the summer, and is fairly constant during both of those periods. I ...
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1answer
695 views

ARMA: modelling a time series with a bimodal distribution

I have a de-trended and de-seasonalized time series, and it's distribution is not gaussian (see distribution in Figure 1). I tried modelling it with and ARMA model, but as we could expect, this model ...
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275 views

Modes and antimodes in apparent trimodal distribution with R

Suppose I have the following white blood cell counts: ...
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707 views

Is there such thing as a discrete bimodal distribution, and how do I go about hypothesising a distribution for my data?

I've got discrete data (highest education level achieved to be exact, where each level has an associated integer, from 1 to 7, with a higher number corresponding to a higher education level). The two ...
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1answer
121 views

What are the ways to model bi-modal target distribution

The target i am trying to regress is clearly a bi-modal distribution, currently one standalone model is giving results which are satisfactory. As I am seeking improvement on my present model, I want ...
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3answers
190 views

Detecting if an 1-dimenisional distribution is Multimodal

I'm writing up some C++ code for one of my Master's coursework. What I'm actually doing at the moment isn't on the syllabus, but I wish to implement it anyway as it will allow me to produce my own ...
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1answer
2k views

KS test for bimodal and unimodal distribution?

I am quite new to statistical tests and not sure how to exactly describe my question. I searched but could not find similar questions. Please do let me know if this is a redundant question. I recently ...
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1answer
203 views

How to detect multivariate binomial distributions?

I tried the hartigans dip test, and it works well for univariate distributions. However, when i tried taking each variable (dimension) and applied hartigans dip test (assuming that if along one ...
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1answer
72 views

How can I estimate the probability that my observed data come from a bimodal population?

I have a data set representing the abundance of a protein in a population of cells. Based on our understanding of the biology behind this, I expect there to be two subpopulations - one in which this ...
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0answers
936 views

fitting mixture of bimodal distribution

I am trying to fit my data with a bimodal distribution using two beta distributions, however it seems to me that the two peaks are not captured very well. The reason that I notice from the data is ...
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3answers
3k views

How to interpret histogram and normaltest result?

I investigated dataset using histogram and normaltest. I used scipy.stats.normaltest, got this result: ...