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

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1answer
30 views

RBF transformation on a Normally Distributed Random Variable

I have a random vector $\mathbf{X} \sim \mathcal{N}(\mathbf{m,\Sigma})$ which is transformed by a Gaussian Radial Basis Function into the random variable $\mathbf{Y} = K(\mathbf X) = \exp(-\lambda ...
3
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1answer
64 views

If I have means and medians, is there a way to average them?

Please consider these data points as an example of many more, they represent single studies with multiple samples which have been done during the last decades. ...
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33 views

Different Central Tendency Measures for Describing Groups or Individuals

Background: I have records with various metrics for many users. I want to develop a profile for each and also group similar users using clustering. Question: When developing a profile for each user, ...
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1answer
14 views

Calculating new averages

I'm studying for a midterm in my basic stats course and came across a question that I'm confused with how it's solved. A manager at a local gas bar has 13 staff members. The average hourly wage for ...
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39 views

Standard deviation of sampling distribution of mean

If we take a sample and calculate the mean, we can calculate the standard deviation for the sampling distribution of the mean using this formula: $\sigma / \sqrt{n}$ But, how many samples do we need ...
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2answers
28 views

What does LS (least square) means refer to?

I have been reading clinical papers and recently come across the term "LS-means", referring to what seems to me as an estimation of some population's mean measure. Obviously, I know what "mean" refers ...
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33 views

repeated measures design of Analysis of variance (ANOVA) with mean not statistically significant and Standard deviation significant

The study area was sampled using a tessellation-based stratified sampling scheme. The area was divided into 50-m × 50-m squares, a point was randomly selected in each square. For each point, a ...
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9 views

Calculate mean and std dev from experiment - no formal params

I am a little lost on how to calculate mean and std dev from an experiment (simulation). I have run the simulation (10000 times) and it output a set of numbers (10000). Plotting a histogram, it gives ...
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23 views

How to create a mean of a variable as a new variable in SPSS? [migrated]

I would like to create a mean of a variable as a new variable. For example, my data consists of individual responses across several surveys. I would like to calculate a mean of all the responses for ...
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1answer
17 views

Unit of Mean and Standard Deviation

can a unit be associated with the mean and standard deviation values or these are "dimensionless" quantities? For instance, if I am computing distance, with unit being meters (m), and I have got the ...
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2answers
229 views

Just “take the average” they say. It's not that straightforward, right?

I have an acquaintance who does not study statistics and doesn't understand that summing data and dividing by the number of data is a summary statistic, i.e. that information is lost. For example, ...
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1answer
20 views

How to calculate standard error between means?

I would like to calculate what is $SE(\hat{x}-\hat{y})$ where $\hat{x}$ is the mean of the first sample and $\hat{y}$ is the mean of the second sample. I know the answer should come out as ...
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2answers
98 views

Ratio of standard deviation to mean

Let's say that we have a confidence interval like this: µ ± σ, where σ is the standard deviation and µ is the mean. I want to know if the ratio σ/µ has any interpretation? Does it mean anything if we ...
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47 views

Sort mean values with deviation

I'm trying to determine what physical attributes of a syllable are important in determining stress. So I have some recordings from different people saying a word, each person multiple times. And for ...
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0answers
23 views

Generate means and std. dev. in a repeated measures ANOVA

I got a repeated measures ANOVA with two timepoints (i.e. variables A1 & A2) as within-subjects dependent variable, and variable B as a between-subject independent variable. In the output (SPSS) ...
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0answers
10 views

A strange R limma voom function mean-variance trend [duplicate]

I am opening a long silent question here because I cannot understand my mean variance trend produced by limma. I am new to RNA-Seq analysis and tried using limma on my data. After voom transformation, ...
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1answer
36 views

Assessing deviation from the mean without Chebyshev's inequality

I have a set of experimental data which comprises distances between successive points: And a simulation which attempts to recapture the experimental data by choosing points at random and ...
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2answers
29 views

Average standard error

I have several measurements from the same population spanning over the course of several years, each year with its own mean and standard error (based on the same replicates at same location each ...
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0answers
46 views

4 cases of Maximum Likelihood Estimation of Gaussian distribution parameters

Let $x_1,x_2,...,x_n$ some normally distributed observations. So $\vec{x}=\begin{bmatrix}x_1 & x_2 & ... & x_n\end{bmatrix}^{T}$ In the context of my research I am trying to estimate ...
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1answer
61 views

Properly calculate mean and SE for meta-analysis

I want to perform a meta-analysis, for which I have data from 30 different experiments, each of them with two different treatments. I have three different types experiments based on how the data are ...
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0answers
26 views

What causes differences in estimates of 95%CI of the mean across subgroups in Stata?

In the small reproducible example, I'm calculating mean of a variable across three groups: ...
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0answers
17 views

Multiple DVs - MANOVA or multiple ANOVAs?

My project has multiple continuous DVs and a single categorical IV. When I run ANOVA for each of my DVs the means and SDs are different to when I use MANOVA. Why is that? Which one is correct? Which ...
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2answers
74 views

Averaging averages and standard deviations

I am comparing exam scores for different subjects: physics, biology, english. I am looking at what proportion of the curriculum is spent on each subject. The number of students is fixed: the same for ...
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1answer
88 views

How can I recreate a Weibull distribution given mean and standard deviation and the shape and scale parameters are unknown?

Figure 2 is a Weibull distribution of three different wind farms in Canada. These 3 probability distributions were combined in a study to obtain a common wind speed model. I will be using this common ...
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18 views

Comparing two data sets for a trend in the data

I have two data sets ( have only access to the statistics of data sets like mean, percentile, count etc but not the data it self). I am interested if I could have a metric which can answer below ...
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16 views

Regarding Bootstrap Hypothesis Test for difference of means, why not absolute differences?

Looking at the Algorithm 16.2 from "Introduction to the Bootstrap, Efron and Tibshirani" I was wondering why isn't the t(.) being tested the absolute difference of the means, instead of the ...
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2answers
53 views

Best way to test that one mean is greater than all the others

Suppose I have $k$ samples of different sizes, each of a different univariate variable. I want to test the significance of the hypothesis that the population of $k_0$ has a mean greater than all of ...
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1answer
11 views

Harmonic mean for averaging predictions?

I have 14 different predictions about each observation in my dataset and I want to compute an overall prediction for each observation based on these. Would it be better to use the harmonic mean ...
3
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1answer
59 views

Transformation among power-means

It is well-known that arithmetic and geometric mean are strongly related via logarithmic transformation, i.e. if we take arithmetic mean of logarithmic-transformed values we get the same as if we take ...
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12 views

Comparing Variance Ratio tests to Hurst exponents

I have used the Chow Denning test and the Hurst exponent (Peng, Whittle and R/S methods) to examine if a particular time series follows a random walk. My results are conflicting between the 2 tests. ...
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21 views

Plotting cumulative average means in ggplot2 [closed]

I want to depict the result of several replications (mean, confidence interval) ...
3
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3answers
115 views

How large does a Poisson distribution's mean need to be to use normal distribution statistics?

As the mean of a Poisson distribution increases, the Poisson distribution approximates a normal distribution. I assume that once the Poisson mean becomes large enough, we can use normal distribution ...
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0answers
20 views

Significance of excess return using geometric mean

Since I am writting an assignement about a contrarian-strategy I have to test if the excess returns are significant or not. I calculated the excess returns this way: geomean(pf_returns) - ...
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1answer
24 views

Why is it necessary to divide by the number of samples when optimizing squared error?

In a lot of different optimization problems, and with particular regard to gradient descent, we use the mean squared error as a loss function. In the formulation of mean squared error, you divide by ...
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2answers
309 views

Calculating SD for normal distribution with only mean and 5% and 95% quantile values

As part of a Bayesian method to estimate the divergence times of species, priors have to be set with values based on previous literature or known fossil dates. These priors can have different ...
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1answer
12 views

Coefficient of determination applied to difference in means?

Assume we have one random variable X, and two groups A and B have different mean X values. Let's say we have another variable Y that has a correlation with X of 0.5. If I wanted to estimate a Y ...
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35 views

Correlation between two samples of different size

I have all price quotes from a stock (to be more precisely CSAN3 from Ibovespa Exchange - Brazil) from 2010 to 2015. I was asked to get the correlation from the log returns year-by-year. This is ...
0
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2answers
83 views

How to calculate mean, median, mode, std dev from distribution

How to calculate mean, variance, median, standard deviation and modus from distribution? If I randomly generate numbers which forms the normal distribution I've specified the mean as ...
29
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3answers
3k views

What can we say about population mean from a sample size of 1?

I am wondering what we can say, if anything, about the population mean, $\mu$ when all I have is one measurement, $y_1$ (sample size of 1). Obviously, we'd love to have more measurements, but we ...
1
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1answer
34 views

How accurate is my simple description of a confidence interval?

Here's my simple words-only description of a 95% confidence interval for the mean. How accurate is it? the sample mean comes from a distribution of possible sample means the sample mean might have ...
2
votes
1answer
26 views

Comparing means of 3 dependent percentages

This is an example of the data that I have. 30 plants are a sample. Each plant has been categorized as percentage of green, brown or yellow color (percentages per plant sum to 100). For example: ...
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0answers
17 views

Relation between bootstrap mean and parameter value estimated via maximum likelihood

I have an observed data set $O$ and a synthetic model $S(\theta)$ which attempts to describe it. By fixing $\theta$ to different values I can generate $M$ synthetic realizations of the model: $$S_k ...
2
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1answer
66 views

Method of meta-analysis of studies to determine mean blood level

Generally meta-analysis is done to determine the efficacy of some treatment as compared to controls. Is it possible to do a meta-analysis of different studies for mean blood level of a chemical, its ...
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0answers
30 views

Should I use a composite standard deviation for these multiple biological/technical replicates?

I used an ELISA to determine protein concentration from absorbance readings, which is a nonlinear relationship. I have 3 sample types, which are broken down into 3 biological replicates (per sample), ...
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0answers
26 views

Alerting framework for incoming traffic using mean or standard deviation

Currently I put hourly traffic (total number of input requests) of my website in a MySQL table. I keep data for the last 90 days. I want to check every hour, lets say 6th hour, that whether the ...
3
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1answer
91 views

How to select the 'best' trim value for the mean function?

I'm experimenting with the trim parameter to the mean function, E.g. ...
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1answer
70 views

Estimating the mean of a variable by controlling for age etc.: Why using median values?

just read this thread here (How do I estimate the mean of a variable for different groups by controlling for age, gender, education...?) and found it very helpful! First of all, thanks for that to the ...
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0answers
34 views

Can we use normal distribution statistics on frequency distribution outputted by bootstrapping?

If I understand correctly, this is the bootstrapping procedure: Pretend sample is population Repeatedly resample from this pretend-population Calculate the mean of each resample. The output of ...
3
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1answer
55 views

How often will sampling distribution of the mean not be normally distributed?

Kabacoff 2015 suggests that if we're not willing to assume the sampling distribution of the mean is normally distributed, we should use bootstrapping to estimate the sampling distribution of the mean. ...
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13 views

Estimate variance from multiple distribution

Suppose I have $N$ feature vector and for each feature I have calculated the mean and variance. Now suppose I concatenate all the feature vector (appending one behind the other) and now if I want to ...