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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Coefficient of variation for nonparametric data [duplicate]

Is it appropriate to use the coefficient of variation (CV) for non-parametric data? I'm not sure whether it is appropriate since you use the mean of the data to calculate it together with the SD. ...
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Generalised coefficient of variation?

Consider the CV for a given random variable $X$: $$ CV_X = \frac{\sigma_X}{\mu_X}$$ Now, say I also have random variable $Y$. Let us define: $$ CV_{X,Y}= \sqrt{\frac{\text{Cov}(X,Y)}{\mu_X \mu_Y}} $...
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dependency of the deviation to the measurement level: how to test normality?

A machine measures the height of some plants. In the context of industrial quality procedures, we repeat the same measurement Hi 10 times and expect the ...
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How to compare two distribution where each point is not from a independent sample

columns are samples and rows are genes. There are two groups. I calculated coefficient of variance (CV) for each group so for each gene there are two CV one for group A and one for group B. I ...
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What does the author mean by “scaled version” of standard deviation?

I was trying to understand how to use XYZ analysis when I came upon this article. The author says that using coefficient of variation of an item (which is a ratio of standard deviation and average ...
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Coefficient of variation values?

I'm doing an assignment on which I'm analyzing a data sample of roughly 1400 soccer players from Europe and I'm not sure how to interpret the coefficient of variation, to be honest. For instance, ...
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How to compare annotations by two groups?

I have two groups of test persons that manually created multiple annotations for different underlying, unknown values (each person created multiple annotations). I'd like to find a statistical test ...
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100 views

Comparing variability of measures across time

I am working with some data where I have measurements for two outputs (Output A and Output B) for 5 participants in an experiment. Each of the 5 participants have both their Output A and Output B ...
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27 views

Coefficient of Variation across Prediction Intervals

I've run into an odd problem that I have a simple answer to but would like to know if there's something deeper to it. I have a data set with 7 observations, each with 2 variables (X,Y). I then run a ...
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Handle data with high variation

I'm analyzing som product data that shows sells over the past day, week and month. In some cases I have a very high number but in most cases this number is quite low, and this is affecting quite a lot ...
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6k views

“covariance” , “covariate”, “coefficient of variance”?

Could you please explain what is the difference of these "covariance" , "covariate", "coefficient of variance"? I would appreciate example from biology if possible
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Relative Standard Deviation (RSD) of more than 100%

Relative standard deviation (RSD) is defined as: $$ RSD = \frac{100 \times s}{\overline{x}} $$ where $s$ is the standard deviation and $\overline{x}$ is the mean. How should a RSD of 170% for a ...
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Is there a statistic or metric that measures variation (or deviation from mean) in a time-dependent manner?

I am evaluating two time series. One has a larger Coefficient of Variation (CV) than the other. But I have also noticed that one of the time series has longer consecutive deviations from the mean. ...
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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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Is coefficient of variation appropriate here?

I am in charge of a large number (100+) of batch computing processes and I am looking for a way to quickly identify which of the processes are 'healthy'. The processes run every day and a duration ...
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665 views

Is a gamma distribution adapted when the coefficient of variation is roughly the same across observations?

Each observation is a distribution of values. Computing the mean $\mu_i$ and standard deviation $\sigma_i$ for each observation $i$ showed that the coefficient of variation (CV) is roughly constant ...
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220 views

How to compare coefficients of variation for lognormal data?

I want to compare the variability of two log-normal samples. They are being summarized as Coefficient of variations (CVs) and I want to test if one sample's CV is different from the other's. To ...
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843 views

Alternative for coefficient of variation due to negative observations

I have several measurements of trees over time (different vegetation indexes). Each measurement is in a different scale, some also include negative values (e.g. NDVI). I need to compare the ...
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682 views

Reproducing Feltz and Miller's (1996) “Asymptotic Test for the Equality of Coefficients of Variation from K Populations”

I'm trying to compute the D'AD test statistic described in Feltz and Miller's (1996) Asymptotic Test for the Equality of Coefficients of Variation from K Populations. I'm attempting to use to R ...
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Different sample size calculations for variable and 1-variable

I am trying to use coefficients of variations ($CV$) to calculate sample size necessary to detect a difference of means ($\mu_0$ vs. $\mu_1$) for a variable that takes on values $x_i \in [0,1]$. I ...
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2k views

Coefficient of Variation with Population Median

I have 2 non-normal population datasets where the median is a better measure of central tendency. To compare the spread of these 2 populations, can I calculate the coefficient of variation (CV) with ...
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1k views

Comparing coefficient of variation

I have three sets of data sets each 10 to 20 data points. I want to test if the coefficient of variation is the same across all the sets. Please suggest relevant methods. I came across papers by ...
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Including the variation within a sample when comparing between samples

I want to include the variation within a sample when analysing the variation between samples. Say I have sample A, B, C. Sample A was analysed three times with the values: 2398, 2383, 2411 Sample B: ...
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Good ICC, bad CV or vice-versa, how to interpret?

I am studying the reproducibility of different methods using the Intra-Class Correlation (ICC) and the Coeficient of Variation (CV). Some methods are presenting an excellent ICC (~.90) and a poor (for ...
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159 views

Coefficient of variation of correlation values

I have the following problem that I am not sure of whether I treat it correctly: I run repeated simulations, where the output of a single simulation replicate is a single correlation value. The ...
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How do I calculate the cv for observation errors from a time series of actual values and a time series of values with observation error?

I have a time series of actual values. I also have a time series consisting of values with observation error. Assuming that the observation errors are normally distributed, independent of one ...
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77 views

Coefficient of variation for shipping

I want to understand if the coefficient of variation ($c_v$) is the right calculation to use for measuring how far off I am when shipping goods to customers. The date I want to ship to customers is ...
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1k views

Estimating coefficient of variation with small sample size

Problem: Estimate coefficient of variation for the mean expenditures for a number of groups. For each group, I have a sample of totals and the counts of people. E.g., for group A, I have totals (...
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1k views

Alternatives to Coefficient of variation

I have a set of temperature datasets all from different products. I wish to calculate the variation in the products. I have tried using coefficient of variation. But because the temperature data ...
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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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203 views

How can one test for difference in variation between two groups of different sample sizes?

I have a question, which has puzzled me for some time now. I hope this community can provide an answer. I have a method which can measure conversion of pyruvate into lactate in the body, the results ...
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579 views

Interpreting standard deviation ratio (is std deviation ratio equal to coefficient of variation?)

I am new in this area. I apologizes if my question is silly. I need to include the homogeneity and heterogeneity of variance as one of the factor in my robustness study.Therefore, i saw this phrase. ...
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552 views

Combining two estimates

The number of participants in a particular sport in the USA in 2014 was estimated by a research group at 3,000,000. This estimate came with a standard error. The number of hospitalizations associated ...
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How to tell a coefficient of variation (C.V.) is high?

I have a group of data series which contain hundreds of values. I've calculated the C.V.s of these data series, but I don't know how I can recognise if they are high or low according to the C.V. ...
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108 views

Alternative to a coefficient of variation

I am currently collecting data 4x per week with a fencing athlete. She jumps with each foot on a separate force plate, so we can see asymmetries in force curves. We noticed that whenever she is more ...
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630 views

How to report a high standard deviation (coefficient of variation)

I have performed a small pilot study in order to investigate whether my experimental method produces lesions of a consistent size between animals. The mean and standard deviation of lesion volume was ...
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Which statistical method can I use to see if there is a correlation between data sets with different size?

For my thesis I want to compare the 3 different test results. If the results are more than 5, samples are failed. And I want to show if these tests are similar behaviour (if there is a correlation ...
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494 views

Coefficient of variation question?

Is it appropriate to compare the coefficient of variation between discrete (e.g., clutch size) and continuous data (e.g., egg width)?
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Ratio of standard deviation to mean

Let's say that we have a confidence interval like this: µ ± σ, where σ is the standard deviation and µ is the mean. I want to know if the ratio σ/µ has any interpretation? Does it mean anything if we ...
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Coefficient of variation for a subset

How do I calculate the coefficient of variation, CV (or Relative Standard Deviation, RSD) for a subset? e.g. ...
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Coefficient of variation for % increase

I was reading about the coefficient of variation and it seems that it can only be computed for ratios (non-negative values). I have a list of values which indicate the % increase in a particular ...
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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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Estimating prevalence of an effect in a RCT study using the overlapping coefficient (and does chocolate make your acne worse?)

I'm trying to tease out prevalence of effects seen from controlled studies, e.g. what % of people would expect to see a higher acne lesion count if consuming 6 oz of cocoa / day? The average effect is ...
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How to interpret the coefficient of variation?

I am trying to understand the Coefficient of Variation. When I try to apply it to the following two samples of data I am unable to understand how to interpret the results. Let's say sample 1 is ${0, ...
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Can Coefficient of Variation be used to verify the representativeness of the mean?

I have a sample with approximately 45 million elements, with 4,410 as the mean and 1,657 as the standard deviation. I am not confident whether or not the mean well represents the sample due to the ...
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Proper use of the coefficient of variation [duplicate]

I have a variety of samples, each with a different standard deviation and mean. The coefficient of variation $CV$ = ${\sigma} / {\mu}$ defines the amount of variation in a population or sample around ...
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Can we use a coefficient of variation as a statistic for testing homogeneity of variance?

There are well-known HOV tests, for example Levene's, Brown-Forsythe's, Bartlett's available in SAS and R. But $C_v$ also deals with dispersion, can we use it to understand the degree of HOV? July ...
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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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547 views

Measure of dispersion for dataset with zero mean

I'm testing a machine learning algorithm which, until now used coefficient of variation in order to relative measure dispersion among different attributes in a given dataset. Now that I need to test ...