# Questions tagged [coefficient-of-variation]

A measure of dispersion expressed relative to the mean, used for positive variables. Equals the standard deviation divided by the mean.

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### What does a squared coefficient of variation signify?

The coefficient of variation is defined as the ratio of S.D to mean, a dimensionless number which on multiplication by 100 gives the percentage of dispersion with mean. But when we square this ...
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### What is the proper method for calculating the Coefficient of Variation of a rate?

I have been asked to evaluate the variation between movement rates of fish within different systems (rates are in km/day). I have between 25-100 samples in each system. I understand that when ...
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### Comparing variation of two datasets of dimensionless quantities

I have a biological dataset in which we measured two dimensionless quantities $x$ and $y$. Let $X = \{x_1,\dots,x_N\}$ and $Y = \{y_1,\dots, y_N\}$ be the vectors holding this data. I want to argue ...
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### Cut off values of the coefficient of variation in determining whether to include/exclude a sample

I'm fairly new to statistics and could use some advice. I have 70 blood serum samples that have had metabolite concentrations tested twice. (Same blood draw, different test dates). I calculated the ...
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### Statistical comparison of data dispersion between two groups

I was trying to find a suitable way to compare the relative data dispersion between two groups and also to investigate if they are statistically significant. During the last weeks, I have searched a ...
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### Normalized statistical measure for agreement of biological replicates

I've conducted an experiment collecting samples from various depths in the ocean. At each depth, I collected 3 samples to act as biological replicates. I now want to show that all of my replicates ...
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### Generalized regression with both additive and multiplicative errors

For measurements of chemical concentrations, it is often the case that the error in the data increases as the true (or estimated) concentration increases. That is, the error is multiplicative and has ...
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### What is the most meaningful method to test whether two versions of the same measuring tool are producing consistent results?

I have got myself confused as to what method will best tell me whether the results from two measuring devices are producing the same results. Basically the subject will wear two devices while ...
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### Compare the variations of data between three groups

I have a data set of particle sizes of grains that are ground by three different machines. I want to test which machine is the best in grinding grains (i.e. the ground particles have the same sizes or ...
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### Properties of CV (Coefficient of Variation) for the sum of normal random variables

Given two normally distributed random variable $X_1$ and $X_2$ given the mean and the variance to be $(\mu_1, \sigma_1)$ and $(\mu_2, \sigma_2)$ respectively, we know that the mean and standard ...
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### Check which parameter causes less dispersion in a sample set - When to use CV (Coefficient of Variation) or CD (Coefficient of Dispersion) etc

The overall goal is to extract/engineer features from approximately 100 segments (various lengths but always more than 80 data points) that are as similar as possible to each other and have a very low ...
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### A high variability in A is associated with outcome X : The use of the Coefficient of Variation to predict outcomes?

I want to know whether the Coefficient of Variation is a valid tool for the following problem: The goal is to assess whether high variability in blood concentrations of a pharmaceutical drug is ...
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### What's the difference between coefficient of variation and intraclass coefficient and when should I use one vs the other?

If I am trying to compare variability in a measurement taken multiple times in a single session with the variability in that measurement taken over multiple sessions, should I use icc or cov? I am ...
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### Calculating interclass correlation but with different observer experience

I have tried finding an answer to the following question both here and using PubMed and google but without luck. I have been asked to calculate the intraclass correlation coefficient from the ...
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### Comparison of dispersion measures of different samples with different subsamples

Context: I have data on movie ratings and I want to find what factors affect the rating the most. I have $k$ features $F_1, F_2,\ldots,F_k$ characterizing a movie - for example, director, lead actor, ...
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### Gamma GLMM Dispersion, Random Effects, and CoV (lme4)

So I know that in glm(), with the Gamma family, one can get the dispersion parameter through the MASS package with gamma.dispersion() or can even look at the summary output as a quick estimate. How ...
499 views

### ANOVA on time series Data

Iāve been dealing with this problem for quite a time. Iām running an experiment with plants growing them with Compost A and Compost B. Iāve been measuring the pH each day at the same time and keeping ...
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### significance testing of unequality of coefficient of variation in multiple samples

I'm performing a study on inter-doctor variation. For that, I'm studying a diagnostic instrument that has around 100 items that all have to be rated. Some are dichotomous, some ordinal. Several ...
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### Model the CV of response variable as a function of CV of predictors

Suppose I have a big county that has 10 farms. In the county, the planting of a crop could happen between March to April. I collected for a given year, the planting date of a crop across the 10 farms ...
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### Distribution of extremes of measurments considering repeated measures

I'm working with measurements for a large sample set and need to quantify the expected extremes. The measurements obviously have some degree of random noise simply in the measurement itself (for the ...
133 views

### Can I compare the average coefficients of variation?

I have two datasets. The first shows a populations choices for mode of transport (3 modes) in 6 different areas. The second shows the same populations responses to concerning attributes (13 ...
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### Combined Coefficient of Variation

I am doing a research in 12 participants where I perform two different techniques three times each, at different moments. I would like to calculate the combined CV (Mean CV1 + CV2 + CV3), but I don't ...
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### Relative Median Absolute Deviation

For example, the CV (coefficient of variation) is the relative standard deviation (sd divided by the mean). Now is there a relative MAD (Median absolute deviation https://en.wikipedia.org/wiki/...
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### Interpreting summary of mixed-effects model R (metafor)

I am a complete novice and was hoping for some clarity around interpretation of my results. Note the response ratio I am interested in is the log coefficient of variation ratio (lnCVR). Please see a ...
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### Measures of dispersion which are scale invariant and can handle a mean of 0

Is there a measure of dispersion which is scale-invariant, s.t. I can compare it between datasets of different scale and does not have the problem like the Coefficient of Variation which is undefined ...
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### Smaller CV for a subsample when estimating mean value of a binary variable?

I'm estimating mean values of a series of binary 0/1 variables / also estimating proportions belonging to each of the two categories for a sample of observations, and again for a subsample of that ...
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### Coefficient of variation for log (base 10) transformed data set

I've recently become aware that there are different formulas for calculating the coefficient of variation (CV). It is my understanding that for numeric data this formula is used CV=(SDTEV/MEAN)100 as ...
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### Calculating the coefficient of variation within pairs

I would like to calculate the coefficient of variation of an assay where I measured each sample in duplicate. I have no statistical background but from my understanding I would need the standard ...