# variance's questions - English 1answer

2.365 variance questions.

### Unequal variances (linear mixed modeling in R)

0 answers, 7 views mixed-model variance linear
I have a dataset as follows: ...

### 4 Are the precision gains from stratified sampling a free lunch?

I'm following the discussion in Field Experiments by Gerber and Green, Chapter 3 as well as these resources: http://ocw.jhsph.edu/courses/StatMethodsForSampleSurveys/PDFs/Lecture4.pdf http://home....

### Comparison of unbalanced groups of values

I know there are several questions (here and on other websites) regarding the comparison of values, but I am still lost with the data I have and the analyses I should conduct. I have just 18 values (...

### 1 principal component analysis or factor analysis to be used with qualitative data

I want to make a model in which the dependent variable is nutritional levels of children, for this, I calculated $z$ scores like weight for ...

### 1 Estimating unobserved variance [on hold]

0 answers, 24 views variance mcmc
I'm analyzing codon usage using the model described in the following paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4494061/ In brief, this model uses a MCMC to estimate the pausing time for the ...

### 2 Calculating the variance of the histogram of a grayscale image

2 answers, 10.731 views variance standard-deviation histogram binning
I am doing image processing and I want to calculate the variance of a histogram of pixel intensities. The first method I have tried: The images store the pixels values using double precision numbers,...

### 1 Paper for the rule of thumb for homogenity of variances

I often read about a rule of thumb, one can apply if the test of equal variances returns a significant result. Depending on the source, the proposed maximal $F$ ratio varies between 1.5 and 4, which ...

### Does explained variance hold for binary data?

0 answers, 9 views variance binary-data
Does explained variance hold for binary data? That is can one use the explained variance truthfully as a parameter with e.g. sklearn's PCA?

### 4 How to estimate posterior variance from dependent MCMC samples? Does the usual sample covariance still work?

1 answers, 38 views bayesian variance estimation mcmc

### 1 Trace plots for MCMC simulations and interpretation of lack of convergence

I am simulating a hierarchical model with MCMC Bayesian methods. The model has three groups of individual effects modelled as random effects drawn from normal priors with mean zero and variances ...

### 1 How to calculate standard errors for GLMs fitted values “by-hand”, without using predicted() in R?

I am running a negative binomial model without creating a glm object in R. I found an answer at StackExchange on how to get standard errors "by-hand" here, but it shows only how to get values on a ...

### 5 How will one determine a classifier to be of high bias or high variance?

The bias and variance of a classifier determines the degree to which it can underfit and overfit the data respectively. How could one determine a classifier to be characterized as high bias or high ...

### Qualitative considerations about the variance of the trend and the seasonal component of a seasonal time series

0 answers, 5 views time-series variance seasonality trend
Given a seasonal rainfall time series X, suppose that I need to divide it into a linear trend (mY+q) and seasonal component. If from the auto-correlation and partial auto-correlation only lags ...

### 1 Assessing distribution of a Likert scales

1 answers, 395 views variance likert scales measurement
I am looking to analyse Likert scales, and want to assess whether there is 'sufficient variation' along the scale [i.e. that the majority of respondents are not 'clumped together' or a particular ...