# variance's questions - English 1answer

2.435 variance questions.

### 2 Inter-cluster variance

1 answers, 1.065 views clustering variance
Can you please help me understand how is inter-cluster (between clusters) variance defined? As opposed to intra-cluster variance which is pretty straightforward, I have not managed to found a clear ...

### 3 MVUE is unique - wrong proof?

Here is the proof of "MVUE is unique" that my lecturer gave: Now I understand the following: The first expansion is done using the formula for the sum of correlated random variables (https://en....

### How to measure how “good” or accurate a probability distribution is? Entropy, variance or what?

How can one measure the accuracy of the probability distribution of, say, a physical magnitude? I know one good candidate is the entropy, which measures the amount of information one has about the ...

### Measuring how well data is evenly dispersed

I am trying to measure how well scores from members of a group are dispersed over possible values. Think of it as a measure of diversity function. Thus, ...

### how do I calculate overyielding in ecological temporal stability

I am investigating diversity-stability relationships and I am trying to test for the portfolio effect and insurance effect with my data. I understand that overyielding indicates the portfolio effect ...

### 35 Variance of $K$-fold cross-validation estimates as $f(K)$: what is the role of “stability”?

TL,DR: It appears that, contrary to oft-repeated advice, leave-one-out cross validation (LOO-CV) -- that is, $K$-fold CV with $K$ (the number of folds) equal to $N$ (the number of training ...

### 1 How to calculate the confidence interval of a line based on its coefficients?

I fitted a mixed model as following: $Y = \beta_0 + \beta_1 T + \beta_2 X + \beta_3 X T + \beta_iW_i$ $T$ is time, $X$ is my variable of interest and $W_i$ are various confounding variables. I also ...

### Consistency of the estimator of the variance of the error

1 answers, 36 views regression variance error consistency
In the classical linear regression model, the estimator of the variance of the regression error is $s^2 = \frac{e'e}{n-k} = \frac{u'Mu}{n-k}$ where u is the error vector, e is the residual vector, and ...

### 1 Finding three coefficients (weight/ratio) by minimising variance

I am finding the value of a,b and c for minimising the variance of the following equation (four variables are correlated): $$Var(\Delta V)=V ar[\Delta S-a\Delta F_1 - b\Delta F_2 -c\Delta F_3]$$ ...

### How can I assess the position of a novel point in among other points

I have data about the nutrient ratio an animal wants to consume and the available nutrient ratio of grasses in it's environment. The data looks like this: The black dots represent plant nutrient ...

### Constant variance in the dependent variable of multiple linear regression

0 answers, 10 views regression variance
There is a question on my homework that says "if variance of dependent variable changes with independent variables, what can you say about a t-test with null: b0 = 0 and alternative: b0 > 0" and I'm a ...

### Variance of the average of two (or more) Net Promoter Scores?

As per Wikipedia, "The Net Promoter Score is obtained by asking customers a single question on a 0 to 10 rating scale, where 10 is "extremely likely" and 0 is "not at all likely": "How likely is it ...

### The variance of the function that is composed of MLE that can't estimate analytically

0 answers, 12 views variance estimation maximum-likelihood
I want to know how to calculate the variance of the function that is composed of MLE that can't estimate analytically. Specifically, I want to know the variance of the estimate of mean of GPD that is ...

### Question on finding the variance

1 answers, 34 views self-study variance arithmetic
]1 For part B, I previously had 2.07 which is incorrect but why?! I literally followed the formula and I encountered a similar problem on the internet that did the exact same thing I did done below: ...

### -1 How to calculate the Var and Covariance of exp(X_{t})+2X_{t-1}?

How to calculate the Variance and Covariance of $exp(X_{t})+2X_{t-1}$? where X is an i.i.d. normal random variables with mean zero and variance one?

### 1 How to assess similarity of two sets of Principal Component Analysis loadings

A predictive model that I currently use relies on PCA with varimax rotation to reduce the dimensionality of the data (whether this is appropriate is a separate question). The dataset consists of ...

### 1 What is error variance?

1 answers, 12.970 views variance error
The term error variance doesn't currently have either a tag here, or a page on Wikipedia. p259 of Colman (2015) defines error variance as: In statistics, the ...

### Variance of linear regression estimator in stratified sampling (survey data)

What is the formula of the linearized variance of the multivariate linear regression estimator in a single-stage stratified sampling design? From the Stata manual, I know the formula for the estimator ...

### Probability - expected value

The random variable $X$ takes on values -2, 0 and 2 with probabilities 1/4, 1/2 and 1/4 respectively. Find $\text{E}(X)$ and $\text{Var}(X)$. Till this part, it was easy enough. Then the question ...

### 1 How do I find the mean of Z = Discrete RV + a Gaussian RV?

I am asked to find mean and variance of Z. (image) Since I am solving a preparatory examen to study, it is not clear to me how to approach the topic because I don't understand the question correctly. ...