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8 views

Increasing sensor resolution by repeat measurement

I have a thermometer which has resolution of 1C. The temperature is measured, the thermometer is reset, and the temperature is measured again. I'm looking for a formula to calculate how many ...
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2answers
71 views

Completely different results after each cross validation

I'm running some classification algorithms in MATLAB and validating them with a 10-fold cross validation. The problem is that every time I execute the cross validation, it gives a very different ...
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0answers
26 views

Warning message after a MCMCglmm call in R

I have a Warning message after a MCMCglmm call in R. Let me first write about the aims of the study : 1) describe whether a set of seven different behavioural traits vary (or are consistent) in time ...
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0answers
26 views

Is it appropriate to transform a dependent variable twice?

Is it appropriate to transform a dependent variable twice, say a lnY and then cubing the ln. The final transformation will be [ln(Y)]^3. I know how to back-transform the results with only the log ...
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1answer
80 views

Statistical significance, repeatability, and sample size (50 shades of grey)

Reading about the problems with significance I wondered how one would approach an experiment in the right way, considering that in practice the sample size cannot be arbitrarily large. While some ...
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1answer
46 views

Assessing Repeatability of a Multivariate Measurement

I have a measurement that was taken 10 times on a sample. The measurement has roughly 11K points. If you're curious, I'm looking at mass spectrum data. I want to determine the repeatability of the ...
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41 views

Assessing Repeatability: Random and Systematic Error

I am analyzing a study where my goal is to assess the quality (precision) of several machines. I have just one true value (measured with the goldstandard) and made 30 runs for every single machine. ...
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1answer
153 views

Repeatability estimation using a mixed model with repeated measures by four raters

I am a medical doctor and definitely not an expert in statistics, although I think I do okay and I am familiar with R. I have discussed the following issue with a statistician but I am still not sure ...
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0answers
51 views

Confidence interval for Repeatability from a lme mixed model

I have a (lme) mixed model of this type: ...
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1answer
49 views

Intra-rater reliability for categorical (non-binary) data with variable observations

Here's what my data look like: From a mark-recapture study on a population of birds, I have data on the coloration score for each individual bird. The coloration score is a simple visual score that ...
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0answers
255 views

Interpreting summary of ICC results in R package “psych”

I have a dataframe "all.st.icc", where 27 subjects have measures of social behavior for each of 8 different years. First four rows of data are as follows: ...
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1answer
242 views

Computing repeatability from overdispersed zero-inflated negative binomial GLMMM in R

I'm trying to compute repeatability of a count response variable from a Generalized linear mixed model with multiple fixed effects and individual ID as a random effect. I'm dealing with both ...
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0answers
37 views

What measurements or tests should I take for testing stability of patterns?

I have a dataset containing behaviours of users. Let's say we have 1000 users and 40 similar tasks. The tasks are similar but the difficulty level vary.To do a task, people can follow 10 patterns. ...
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70 views

What is a “subject” in ICC?

I have been working in R and have finally got some code working regarding intraclass correlation coefficients. In the output I get something called "subjects". I thought it was to do with the number ...
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1answer
2k views

How to compare repeatability (ICC) of different groups?

I have calculated the ICC values for two groups and would now like to compare the ICC values to determine if the groups differ in their repeatability. In the literature people have simply used t-tests ...
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1answer
162 views

Determine individual consistency from mixed model?

To investigate the difference between three tasks I tested 30 individuals on each of the three tasks and ran the linear model as follows: ...
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0answers
638 views

How to analyze intra-rater reliability with 31 raters who all rated 4 subjects twice

I'm trying to analyze the intra-rater reliability of an occupational therapy assessment. The assessment consists of 57 items, where some items are ratio data and some items are ordinal data. In my ...
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5answers
538 views

How to assess repeatability of multivariate and method-specific outcomes?

Method "A" describes biological samples using multivariate "fingerprints" that consist of about 30 different variables. Different variables show different typical distribution and many of them closely ...
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2answers
541 views

The use of xtmixed with the quickicc command

I am attempting to do a icc using the quickicc command following the use of xtmixed. I'm attempting to check repeatability in a ...
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2answers
136 views

How to assess whether experimental measurements obtained from different technicians are biased?

Suppose I have a list of measurements from an experiment; for example, 34 31 55 18 19 22 44 48 23 . . . But I then learn that these experiments were conducted by two different technicians, so I ...
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1answer
2k views

Computing repeatability of effects from an lmer model

I just came across this paper, which describes how to compute the repeatability (a.k.a. reliability, a.k.a. intraclass correlation) of a measurement via mixed effects modelling. The R code would be: <...
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1answer
582 views

Confidence intervals for repeatability

I have calculated the repeatability of individuals' responses to a stimulus using the methodology of Lessells & Boag (1987) Auk 104:116, where repeatability r = among-groups variance component / (...