# Questions tagged [circular-statistics]

Directional statistics (also called circular or spherical statistics) is the discipline of statistics that deals with directions (unit vectors in $\mathbb{R}^n$), axes (lines through the origin in $\mathbb{R}^n$) or rotations in $\mathbb{R}^n$.

247 questions
Filter by
Sorted by
Tagged with
10 views

### Modeling repeated measures analysis with circular variables

(question cross-posted to stack overflow here:https://stackoverflow.com/questions/72189932/circular-analysis-repeated-measures-design-model-building-evaluation-and-inte?noredirect=1#...
1 vote
21 views

### How to calculate the value (wind direction) of "maximal effect" in a linear-circular correlation?

I am trying to evaluate the effect of wind direction (circular variable) on a dependent linear variable. I have used circular-linear regression to find the correlation coefficient between the two ...
• 21
60 views

### Which statistical test should I use to see if the month of onset of a disease is random or clusters in the winter?

I have data showing which month a disease started for 119 subjects. The months are represented by 1-12 (Jan - December). We hypothesize the disease more often onsets during winter months. What test ...
• 33
15 views

### Loss Function for Polar Coordinates Target Variables?

Suppose I want to do regression on targets that are polar coordinates. What loss functions are appropriate? I know I could always use mean squared error, but I'm not sure that's the most appropriate.
1 vote
21 views

### How can I quantify this non-linear relationship where y-values peak within a narrow range of x-values?

I have plotted this data, and to me there appears to be a clear relationship between the variables (sediment accumulates when wind direction is between 150 and 250 degrees). Is there a appropriate ...
• 21
31 views

### Multiple regression for circular (periodic) target [duplicate]

Please kindly provide some advice on maximizing regression accuracy with a circular target, in this case, angles between 0 and 2pi. The training set has the shape (14585110, 6). The angle information ...
954 views

### Why doesn't mean square error work in case of angular data?

Suppose, the following are the first few lines from a dataset for solving a regression problem: ...
• 1,518
30 views

### Machine learning regressor for cyclic values

I have a question regarding training a Machine Learning regressor for cyclic values. For instance, consider phase values. We cannot use conventional regression methods for this as for example the ...
• 151
143 views

### Why does the von Mises-Fisher distribution need two parameters?

The von Mises-Fisher distribution has two parameters: the mean $\mu \in \mathbb{R}^p$ and concentration $\kappa \geq 0$, where $\mu$ is constrained to have unit norm. Why not instead define the ...
39 views

### Variance of von Mises-Fisher Distribution

As a follow up to this previous question on the expectation of the von Mises-Fisher distribution, what is the variance of a von-Mises Fisher distribution as a function of the mean direction $\mu$ and ...
38 views

### Best practice for cyclical feature encoding for tree-based methods

Right now I'm facing a dataset of professional road cyclists which contains training data of the athletes at different dates over two years. For some tree-based methods I'm still looking for a 'best ...
• 218
543 views

### Fitting sine wave with lm in R for circadian activity- frequencies?

I'm trying to fit a sine wave over some activity data, just like this post. I've managed to get a reasonable looking graph for one condition: However, when I plot the other condition the wave looks ...
32 views

### Best distance measure for cluster analysis of time series data with a circular variable

I'm doing hierarchical clustering on a set of time series (say 21 time series of 400 time points), however the variable I want to cluster is a circular variable, i.e. a directional vector between 0 ...
160 views

### How to define distance for vector of angles?

I have a vector of angles and I am looking for a method to compute the distance of my vector with any other vector of angles? I am looking for something similar to Euclidean distance but I know that ...
• 151
347 views

### Measure of similarity between two distributions - with variable starting point (wrap-around)

I would like to compute the (dis)similarity between two distributions. The first represents tones sung by an experimental subject during a recording. There are different numbers of tones, each with ...
• 1,548
25 views

### Different methods for evaluating skewness of circular data

I am trying to find skewness of circular data. As far as I understood, there are different methods for this. For example these methods: Pewsey, Metrika, 2004 (link) Statistical analysis of circular ...
• 151
128 views

### use GAMM models for full circular wind direction data

using a GAM modeling approach enables to include circular data as fixed effects. I wish to analyze the effect of wind on the flight behaviour of birds. In order to do so I want to add wind speed and ...
• 1
55 views

### Skewness of Von mises distribution using two different methods

I want to use skewness of circular data using circ_skewness code in MATLAB. I know there are two methods for this: Pewsey, Metrika, 2004 Statistical analysis of circular data, Fisher, p. 34 However,...
• 151
22 views

### Appropriate to rescale kernel densities to radians and use watson's two sample test of homogeneity?

I'm looking at activity budgets of animals derived from camera traps and gps collars. I'm pooling multiple cameras or gps collars within each group before comparing the activity of two groups against ...
• 103
255 views

### Converting a circular outcome variable to a linear one

I have a problem where I want to measure deviations from zero degrees. This outcome variable is a circular measure, since a deviation of -180 degrees is equivalent to 180 degrees. However, I don't ...
• 125
73 views

### Skewness and kurtosis of VonMises distribution

I could not find a reference that has mentioned the skewness and kurtosis of a circular data that has Von Mises distribution. What are the values? and it is great if someone can introduce some ...
• 151
27 views

### Covariate analysis comparing distributions / means of circular data

Are there publicly available software packages to run an analysis comparing the means or distributions of two samples of circular data with the presence of a covariate? If not, are there ways to ...
• 125
90 views

### Two sample Kuiper test for checking normality of circular data

I have circular data and want to check whether it is a normal (Von Mises) distribution or not. I do the following steps: Create a Von Mises distribution with the same mean and kappa as my main data. ...
• 151
348 views

• 53
1 vote
15 views

### Perfomance comparison of circular mean estimators with long-tailed noise

I am trying to compare the performance of two estimators of the mean of a circular random variable. One of these estimators gives estimates with lower absolute error but only for samples that are ...
1 vote
237 views

### Calculating the trend of an angle when it crosses 360 -> 0

I have a variable that measures an angle describing the relative position of two objects (i.e., can range from 0-359), and I would like to quantify how this has changed through time. For example, here ...
• 135
1 vote