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Questions tagged [means]

In probability and statistics, mean and expected value are used synonymously to refer to one measure of the central tendency either of a probability distribution or of the random variable characterized by that distribution. For a data set, refers to a central value of a discrete set of numbers: specifically, the sum of the values divided by the number of values.

In probability and statistics, mean and expected value are used synonymously to refer to one measure of the central tendency either of a probability distribution or of the random variable characterized by that distribution. For a data set, refers to a central value of a discrete set of numbers: specifically, the sum of the values divided by the number of values. Reference: Wikipedia.

For a finite population, the population mean of a property is equal to the arithmetic mean of the given property while considering every member of the population.

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Mean of minimum of an inverse Rician random variable

What is $E\left[\min\left(\frac{1}{X}\right)\right]=?$, where $X$ is a Rician distributed random variable. I know from this article that the first moment of an inverse Rician distributed random variable is $E[Y] =…
hbcelebi
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Nice mean for negative Numbers

I'm searching for a nice mean (or average) for negative numbers that gives less weight to high (absolut) outliers (I don't have enough values to use median). Obviously the way to go for positive values is the geometric mean but this is not working…
PAS
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How to know whether a question asks for an average rate from a time or distance perspective?

I have a sample problem: Bob travels up a hill at $X$ miles an hour and down the hill at $Y$ miles an hour (You can assume that the length of the trail going up is the length of the trail going down in terms of distance). If a question were to…
Mario Ishac
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Exam means problem

In a class I have a note on a scale of 1 (low) to 100 (high). If I get 71 on my next exam, my exams mean will be 83. If I get 99 on my next exam, my exams mean will be 87. How many exams did I already have? I've made a small python program to…
Olivier Pons
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Average of sum and Sum of average of 2 random non zero distributions of numbers

Suppose we have $$A_i \sim N( \mu_a, \sigma_a)$$ $$B_i \sim N( \mu_b, \sigma_b)$$ Where $A_i$ and $B_i$ are i.i.d. respectively, where $i = 1 \ldots n$, We are interested in $$\frac{ \sum_{i=1}^{n}{ \frac{A_i}{ B_i} } }{n}…
Jack Pedley
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How to iterate the geometric mean

I've been looking for the formula of the rolling geometric mean, which could be calculated iteratively, i.e $G(x)=f(G(x-1))$. This is needed for the computationally efficient spreadsheets.
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Why the mean of a quotient is not equivalent to a quotient of means?

I have a problem where I am deciding upon the correct order of operations. I have two 2-dimensional matrices that I wish to divide in an element-wise fashion. Both matrices have dimensions $256 \times 256$. Say that I wish to divide Matrix 1 ($M_1$)…
Matt
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Some comparison questions related to the harmonic mean

I am an economist, and in a research paper I am working on, I came accross an harmonic mean. I am not very familiar with this kind of mean, and did my best to study the topic, but I have a few questions I am not sure how to think about (and…
Laurent Simula
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I am trying to "scale" one set of data to another set based on minimum, maximum, and means of the latter set.

So hey guys, I'm the guild master of an MMO guild that uses a point system for determining the order that loot is handed out. We are merging into another guild with a different point system. One of my goals during this merger is to merge our point…
Nathan Young
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Mean of 10 nos. is given. Values of 8 of these is increased by 15%. Can I get to know the new mean if I know whether the 8 nos were top 8 or bottom 8?

It is a data sufficiency question. We have to tell whether the question can be solved using one of the two options given below, both of them, either of them, or if it can't be solved even if we use both the options together: Q. Last year the average…
ANANYA AKHOURI
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The average of the items of $(0,10]$

The question says it. Let $A = \{\,x \,|\, 0 < x \le 10\,\}$. What would be the average of all the items in this set? How do you prove it? UPDATE $x$ belongs to the set of real numbers.My thoughts:Is it possible to find the average of the items of…
user668217
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Average of a dataset with Ranges of Numbers - A "Simple" high school standarized test question

This is similar to a question on a standardized test for high school students: The heights of students are listed below. What is the mean of this dataset? The dataset is: 1 student 55-56 inches, 1 student 57-58 inches. The first thing that confuses…
dan dan
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Is the mean of a set of numbers always greater its "mean decomposition"?

Is the mean of a set of numbers (arranged in decreasing order) always greater its "mean decomposition"? For simplicity, assume that all the numbers are distinct. Here's what I mean by "mean decomposition": Let's say you have three numbers…
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Arithmetic and harmonic mean of two numbers.

What is the maximum value of arithmetic mean of two integer number if their harmonic mean is 40? $$\frac{1}{x}+\frac{1}{y} = \frac{2}{40}$$ $$xy=20x+20y$$ $$xy−20x−20y+20⋅20=400$$ $$(x−20)(y−20)=400$$
user518463
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Arithmetic mean vs Harmonic mean

I am reading about Arithmetic mean and Harmonic mean. From wikipedia I got this comparision about them: In certain situations, especially many situations involving rates and ratios, the harmonic mean provides the truest average. For instance, if a…
Utshaw
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