# Tagged Questions

The expected value of a random variable; or a location measure for a sample.

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### How do I find the mean of a sample mean?

Random sample size of 100 with a mean of 50 and a SD of 10. How do I go about finding the mean of the sample mean? Thank you i advance.
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### Aligning distribution vs aligning subspaces [on hold]

Does aligning the distribution of two datasets via minimization of the maximum mean discrepancy also align the two subspaces that span the data?
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### compare means of variables with unequal N Sizes of a population

I am trying to compare means of 4 variables and the var have unequal N sizes with some missing values. According to the figure attached, can I compare mean of B with mean of C variable ? B has a lot ...
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### Calculating Standardized Response Mean

I was told that standardized response mean was calculated as "absolute mean change divided by the standard deviation of individualsâ€™ change in score." But, other websites say "the difference between ...
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### Which test can I use to compare two count data means with a lot of zeros?

Suppose I have two count datasets, lets say the count of tigers across different years at two places. Now for most of the years we have 0 tiger sightings. For eg. ...
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### Is median age at death better than mean age at death [closed]

In reporting age people died is it better to use median or mean? At the moment where I work it's mean (average) but I think median might be more useful. We have to report weekly deaths in the country. ...
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### Expectation and variance of sample mean with random sample size

I have a question regarding sampling where the sample size itself is a random variable. Say I have two sub-populations $A$ and $B$ from which I can sample a real valued random variable with ...
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### Is an independent t-test the right choice for this question?

I was trying to figure out which test I need for analyzing my data. However, I guess by reading that much I confused myself. I analyzed two different retailers with respect to the availability of ...
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### How can I calculate variance of a very large random variable?

I'm implementing an algorithm which recieves as input samples from a random variable with an unknown distribution. The random variable is extremely large so my input is logarithmic, and still large (...
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### Looking for a test for a very specific mean of means situation

There is a very similar post to this one, and I am more going off of what has already been asked, than asking a new question. See post: "Test for comparing "mean of means"" The answer ...
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### Probability than empirical mean of one binomial RV smaller than another

Lets suppose I have two binomial random variables: $X \sim B(n_1, p_1)$ and $Y \sim B(n_2, p_2)$. I would like to calculate the probability than the empirical mean of $X$ be smaller than the empirical ...
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### Estimate of parameter of exponential distribution with binned data

I have the following data, which can be modeled by exponential distribution ...
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### Comparing different scale ranges for one Likert scale instrument

I don't believe this exact question has been asked before. I am conducting a meta-analysis on a certain Likert scale survey instrument that has been psychometrically validated. It is a 16 question ...
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### How do I generate appropriate group-level coefficients and standard errors for my regression?

I ran a mixed logistic model testing the influence of group (two-level) on a binary outcome, and I want to report the group estimates and their SEs in graph. However, I can think of two ways of doing ...
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### Weighted mean / average where you reward the lowest value / cost / distance

Best I've several weather-station (200), placed across the country (508 municipalities). Now, I would like to prescribe the weather info, e.g. temperature, to each of the municipalities of that ...
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### What mean should be used for the variables that are involved in a linear regression model in a log-transformed space?

This has been bothering me for a while. Both $X$ and $Y$ are material properties. They can be described using a linear regression model built in the log-transformed space, i.e., $\log Y=a \log X+b$. ...
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### How does one go about determining the standard deviation of an entire sample data set?

I have frequently been faced with analyzing csv files that are limited in length to approximately 32,000 records in length (overflows at 32,768, from signed integer limits on a 16 bit wide data bus). ...
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### Is it valid to derive a mean from categorical data?

I am working on a study to quantify average working hours for doctors. However, when I leave it empty for respondents to fill up, it remains unfilled. Changing it into categories as above yield ...
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### Classification of real values

I have values of attribute between 0 and 1 which i want to predict. The distribution of values is shown in fig. I want to predict this attribute. The problem is there are around 15 classes in this ...
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### Variance of subsample?

Total sample = subsample 1 + subsample 2 I have the mean and variance of total sample and subsample 1. I have n for total, subsample 1 and subsample 2. I can calculate the mean of subsample 2 ...
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### Combine multiple means and upper/lower standard deviation values

I need to combine the means and upper/lower 1 sigma values for three different estimates of the same parameter. For example, a given set of means (m) and upper/...
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### Comparison of two means when they are means of means?

I have two vectors "A" and "B". Each vector contains multiple mean values derived from observations. The two vectors are subsets of a sample that has been categorised into five vectors. All vectors ...
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### mean\medians as data points in two way repeated measures ANOVA

I have a table with 12 columns each regarding one combination of three (2X2X3) diffrent conditions in an experiment. Each row (25) represent a subject that did the experiment. Each data point in the ...
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### What is zero mean and unit variance in terms of image data?

I am new to deep learning. I am trying to understand some concepts. I know "mean" is an average value and "variance" is deviation from mean.I have read some research papers, all say that we pre-...
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### Confidence intervals for group means (R)

Here are some sample data in R: set.seed(42) df <- data.frame(g = factor(rep(1:2, each= 50)), y = rnorm(100)+rep(0:1, each=50)) One can easily get group means ...
The sample mean is $\bar X = \frac{1}{n}\sum_{i=1}^n X_i$ and the sample variance is $S^2 = \frac{1}{n-1} \sum_{i=1}^n (X_i - \bar X)^2$ Can someone please explain how the sample mean and sample ...