# Questions tagged [mean]

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

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### Given two rvs $X$ and $Y$, if $X Y = Z$, is it possible to change the mean and sd of $X$ without changing the mean and sd of $Y$ and $Z$

I have two lognormal rvs $X$ and $Y$, and a third rv $Z$ which is the product of the former two. I know the mean and standard deviation of the three. Is it possible to calculate an alternative pair of ...
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### Calculating proportion

I have a dataset of 10 people who share the cost of a service at the end of each month. The cost of the service is constant. Is there a fair way to split the cost of the service such that the ...
1 vote
12 views

### Diffrence in probability distributions of seperated groups

If I were to measure some quantitavie metric of a sample population and record its mean, and then I were to split by random selection all members of the population into two groups of equal size and ...
15 views

### Descriptive Statistics for Zero-Inflated Dataset

Just as titled, I'm curious as to what should you choose to represent a measure of central tendency for a zero-inflated vector or such. My background says go "mean" if normally distributed, &...
1 vote
83 views

### With more labelled samples in a grouped dataset, to check the correlation with another, is it better to duplicate samples or take the means? [closed]

Another issue is that dataset with more labels in groups, they have less deviation intra groups vs inter groups. So I could take the means of them (the 'second' index), or the whole label means (the '...
119 views

### Multiple correlations across subjects

I have a bunch of data where I am recording two variables across time for many subjects: velocity of the right hand, and intensity of the speech. For each of my 20 subjects, I have ~30 recordings of ~...
19 views

### A T-test for difference of means and normality assumption [duplicate]

I am a little bit confused about normality assumption in T-Test for difference of two independent means. My reasoning now as follows: If the distribution of the populations are non-normal, it's ok as ...
16 views

### Is there a difference between Principal Component and weighted mean using PC loadings? How to get Principal Component on scale of original variables?

I was interested in doing a Principal Component analysis but returning a Principal Component on the scale of the original variables. Principal component analysis in R defaults to scaling and centering,...
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### What would be the optimal model for continous data across 5 time points?

We are searching for the best model to represent continuous data of gene expression logFC (Y-axis) across 5 time points (X-axis), where the trend line would follow the mean expression on each day. ...
1k views

### How to calculate standard deviation when only mean of the data and sample size is available?

Many a times it happens that you get comprehensive data at a group level and you have to compare one group against another but you don't have the data points separated. In these cases, how do we get ...
33 views

### Demeaning binary variable

I was confused regarding fixed effects regression model. Suppose I have a panel dataset with data on firms across several years. Introducing firm fixed effects and estimating deviations from means (...
1 vote
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### How to report a difference in means - Demographics

First of all sorry for the question, I'm having a hard time with statistics :) I have conducted a survey for my thesis and am currently analyzing and reporting the results. At the end of my survey, I ...
20 views

### Paired sample t-test to compare the accuracy of missing data imputation methods

I have an assignment to compare an original data set (N = 100, 14 variables, 5 of which are nominal) with complete values to another version of the same data set with missing values imputed from 3 ...
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### Computing the Mean of Twice-Measured Ordinal Variables for Individual Participants: Is it Valid?

I am conducting a 2x2 study with ordinal independent variables. Participants are asked to rate two different instances of the same independent variable condition. For instance, participants in the '...
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### How to explain discrepancies between contrast estimates and mean differences?

(I'm working with R but the core of my question is about statistics.) I'm using a quasibinomial model in R with a dependent variable and several independent variables (both numeric and dummy variables)...
227 views

### Is it acceptable to take the mean of a bunch of median values?

I use a Bayesian latent variable model to construct a time series cross-sectional measure of corruption for all countries in the world from 1960 to 2010. For each country-year observation, I obtain a ...
20 views

### R summarize predicted value by groups from multiple datasets

I ran mice function and generated 3 mice imputed datasetes. I have a nonstandard model that is not supported by with function so. I used this example and ...
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### Estimating the mean of a Poisson process from data

My data shows the daily number of logins per person over the last three months. I am modelling the number of events per person per day as a Poisson process. I am interested in estimating the ...
1 vote
37 views

### The Tsallis entropy of generalized Gaussian distribution

I would like to discuss the computation of the Tsallis entropy for the generalized Gaussian distribution. From the paper in the link https://www.sciencedirect.com/science/article/pii/S0167947322000822....
1 vote
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### Covariance between sample mean and sample standard deviation

I am trying to figure out the covariance between sample mean and sample standard deviation. The only related post I can find here is this: asymptotic covariance between mean and standard deviation and ...
357 views

### Covariance between sample mean and sample variance

I am trying to figure out the covariance between sample mean and sample variance from a population. We DO NOT know whether the population is normal (if it's normal, then the covariance is zero between ...
1 vote
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### Error between average of averages and true average [closed]

It is known that the average of averages can yield an incorrect result as compared to the true average. The classroom example comes to mind: if the test results of class A is [50, 60, 100], class B is ...
11 views

### Aggregating metrics at parent

I have a model with several independent variables/metrics that each additionally has a corresponding unit, pre-defined upper/lower bounds and a desired value. Now I wish to compute some basic ...
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### Why are the AD, ACME and Prop. Mediated identical for control and treated groups in mediation analysis?

I have conducted a basic mediation analysis using mediation::mediate. My treatment variable (X) is a binary variable with two groups. My mediator and outcome variables are continuous. I also have a ...
1 vote
45 views

### Can I use Welch's t-test on proportion data?

I have conducted a Welch t-test to see if the group means in a school's average progress 8 scores (a measure of education attainment) are different for rural and urban schools. I also have data on the ...
56 views

### Calculate confidence interval of mean difference - in R?

I'd like to calculate the confidence interval of the mean difference. I know that you could potentially use the t.test function in R for this but I can't use the original data, of which the means have ...
1 vote
117 views

### Understanding the Weighted Bootstrap

I have recently learned about the idea that it is possible to bootstrap "weighted" data - for example, suppose we have: A set of sample means : $\bar{x}_1,\bar{x}_2,\ldots,\bar{x}_k$ The ...
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### How to convert standard error of the mean (SEM) into a percentage change

I have performed a t-test between groups, but I only have Mean, SEM, and N. Now I would like to look at the percentage change between these two groups, and compare this percentage change to another ...
760 views

### Can any quantity be bootstrapped?

Suppose we have the median incomes of 150 different countries (in each country, the median income was calculated on a sample of people) - we don't have the individual incomes of each person in these ...
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### Mean of Medians? Median of Means?

This is a question I have wondered about for a long time and have never been able to find a full mathematical explanation behind this. Suppose there are 100 countries. As an experiment: We give Person ...
1 vote
45 views

### When can I average the averages?

Let's be straightforward to my case. I'm building a matchmaking system where it produces groups of players. Each player has a weight that is obtained from his/her skill and experience. A group is good ...
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### How to impute the std deviation of a sample using the pooled mean and standard deviation of similar samples?

I want to perform a meta-regression based on the mean changes from baseline values.In one of the studies, the standard deviation has not been mentioned. How can I impute the value of the missed ...
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### Why is there different Geometric Least Square Means for same treatment?

According to the study protocol, we used the MIXED model technique (in SAS) to estimate the ratio for example C vs A , C vs D, and its 90% confidence interval. However, in the ANOVA output, for ...
20 views

### Mean-centerinfg for logit values?

I have a question regarding the logistic growth model. Can proportion values that have been converted into logit be mean-centered? When we calculate the actual difference value between two proportion ...