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

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1answer
17 views

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.
0
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0answers
5 views

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?
0
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0answers
11 views

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 ...
0
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0answers
22 views

Calculating Standardized Response Mean

I was told that standardized response mean was calculated as "absolute mean change divided by the standard deviation of individuals’ change in score." But, other websites say "the difference between ...
2
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0answers
14 views

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. ...
-1
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0answers
19 views

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. ...
4
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0answers
52 views

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 ...
0
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0answers
21 views

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 ...
2
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2answers
84 views

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 (...
0
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0answers
15 views

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 ...
0
votes
1answer
19 views

Average of Average Quantities and Their Associated Error

consider the measurements: $x_1, x_2,x_3$. Each is the average value of some sample $x_{s1}$ of the physical quantity $x$ that is measured on a nodal point $i$. $x_1 = \frac{1}{N_1} \sum_{i=1}^{N_1}...
2
votes
2answers
76 views

what to do when outliers are identified?

In one task that measures the times that participants take to respond to each item of a task some of the response times were considered outliers as they are more than 3SD above the mean of the ...
0
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0answers
15 views

Arithmetic vs Geometric mean for absolute error of a rate [duplicate]

What is the most appropriate average to use if I want to compute the average of the absolute error of a rate? Example: This sounds a bit complicated, so let me break it down. Suppose I have a box ...
0
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0answers
24 views

Statistical signifiance between two related populations

I have the mean of the number of people below the poverty line for census tracts for the entire state of Washington and also for census tracts of selected counties within Washington. The means come ...
1
vote
1answer
41 views

probability distribution function and quantile function for normal distribution in R

I've studied statistics before but I've forgotten quite a lot, but decided to pick it up again along with learning how to use R. I need help with this question: (I've translated from my Swedish book ...
23
votes
3answers
2k views

What can one conclude about the data when arithmetic mean is very close to geometric mean?

Is there anything significant about a geometric mean and arithmetic mean that fall very close to one another, say ~0.1%? What conjectures can be made about such a data set? I've been working on ...
0
votes
1answer
40 views

Can I run statistical tests on descriptive statistics like mean and standard deviation? (i.e. no raw data)

I'm trying to figure out which statistical test to run on my data, but it has been processed so that now I have gathered the mean and standard deviation values to be used instead of the raw data. I ...
4
votes
1answer
60 views

Why is the mean of a Chi Square distribution equal to the degree of freedom?

Is this part of the definition of a Chi Square distribution? Or is it deduced from another property? In which case, what is the proof?
0
votes
2answers
59 views

Mean of the product of n dependent indicator random variables

How can I simplify $E( I_1\cdot I_2\cdot \dots \cdot I_n )$, which is a mean of the product of $n$ dependent indicator random variables. Can I write down something like $E( I_1\cdot I_2\cdot \dots\...
2
votes
0answers
56 views

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 ...
6
votes
2answers
105 views

Estimate of parameter of exponential distribution with binned data

I have the following data, which can be modeled by exponential distribution ...
1
vote
0answers
26 views

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 ...
3
votes
0answers
26 views

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 ...
0
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0answers
5 views

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 ...
1
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1answer
32 views

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., $\log Y=a \log X+b$. ...
3
votes
1answer
64 views

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). ...
7
votes
3answers
470 views

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 ...
0
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0answers
20 views

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 ...
4
votes
1answer
70 views

Maximum of a set of values from given mean and median

The arithmetic mean and median of $5$ distinct natural numbers are both $7$,what may be the maximum of the $5$ numbers? Here we see that the median is the $3rd$ value.Also the sum of the numbers is $...
5
votes
4answers
309 views

Should I use an average to summarize ordinal data?

I need to work out a "average" (for lack of knowing a better word) of ratings or perhaps I could call them labels. Basically, I have a list of words that have been rated 1 - 3 for difficulty. 1 being ...
2
votes
1answer
32 views

How to get a mean from multiple categorical fields

I have some census data on income I would love to analyze. But income, in the data, is split into different income groups, each group is a column containing the number of people in an area that earns ...
2
votes
0answers
15 views

Higher variance in sample mean or sample median? [duplicate]

The variance of the sample median depends on the distribution you are sampling from. This is also true for the variance of the mean. But can one say that the variance of the sample mean is always ...
1
vote
3answers
19 views

What statistical method should I use to filter out the correct point?

My project is in the field of image processing. The output of a certain program would print the x and y coordinates in the image. I calculate the arithmetic mean of the points to get the mean ...
0
votes
1answer
29 views

Inference about two samples

I have two different large samples, one is normally distributed (0,1) and the other one follows a t-distribution (df = 4). Can I compare whether the means or the st. deviations of both samples are the ...
1
vote
0answers
21 views

Weibull, Gumbell and Extreme Value: from mean and variance to shape, scale and location parameter

I need to sample random numbers from Weibull, Gumbel and Generalized extreme value distributions. Of all of these distributions I know mean and variance. My question is: how can I determine these ...
0
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2answers
29 views

Co-Variance of Zero and Non-Zero mean random variables

Is the value of co-variance function for non-zero mean random variables different from the value of co-variance function when random variables have a zero-mean? I think yes based on this: For a ...
0
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0answers
17 views

Standardized difference of means for multiple classes

Standardized mean difference is very straightforward when you have 2 distributions / groups. How is this metric computed when you have >2 groups? Is there a better alternative to determining the ...
0
votes
1answer
36 views

Calculating Standard Deviation of the Volume of a Cube

Let's say I have a machine that makes cubes. My goal is to determine the average and standard deviation the volume of a cube. I have N length, width and height measurements. I do not believe these ...
0
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0answers
14 views

What n to use for significance of correlations in three different scenarios

I feel these questions might already be answered around here somewhere, but I was not able to find it, so here goes. 1) General case of time-series When determining the significance of a correlation ...
0
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0answers
22 views

panel data mean and standard deviation

I have panel data of the form $r_{it}$ i.e. I have repeated observations of the random variable $r$ varying over individuals (i) and over time (t). Let's assume I compute the grand mean and sd of ...
1
vote
1answer
39 views

Robust statistic for representing small dataset with outliers and representing them graphically

I'm evaluating different systems varying a certain parameter common to all of them. Let this parameter be x. At each x value I ...
1
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1answer
25 views

Calculating speedup confidence interval

Summary I'm trying to calculate the confidence interval for speedup of a program when I have many measurements for the old and new execution times. Details Speedup is calculated as: $\frac{time_{...
0
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0answers
29 views

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 ...
0
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0answers
13 views

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/...
2
votes
0answers
27 views

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 ...
0
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0answers
34 views

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 ...
0
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0answers
62 views

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-...
1
vote
1answer
51 views

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 ...
3
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1answer
61 views

Negative variance result when calculating standard deviation

Please note, I am still in secondary school so please keep your answers simple. A question on my homework states to calculate the standard deviation from a given frequency table with several class ...
-1
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1answer
37 views

Sample mean and sample variance [closed]

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 ...