The sum of several numbers divided by their count nicely summarizes the overall size of the numbers involved in a single value.

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-2
votes
2answers
19 views

Calculate occurance of a digit in average [on hold]

Scenario: We have an average of say $1.25$ from a total of $20$ numbers. The numbers consists of $1$s and $2$s. In this case: $$2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1$$ Amount of ...
1
vote
2answers
42 views

Mean age among employees in a company.

In a company there are 32 men and 59 women. Male mean age is 48.5 and female 39.2. One of the women (47 years old) ended working at the company and was replaced with a 23 year old man. Calculate the ...
1
vote
1answer
32 views

Average distance between two random points in a square

A square with side $a$ is given. What is the average distance between two uniformly-distributed random points inside the square? For more general rectangle case, see here. The proof found there is ...
-3
votes
0answers
10 views

Analyze mean in difference in before and after measurements [on hold]

I am trying to decide the best way to measure the realationship in the difference between the before and after measurements of a single group. So say I measure the weights of a group 6 ...
-4
votes
0answers
29 views

What is the average thickness of a Chinese book? [on hold]

The thickness of a shelf and the thickness of 80 Chinese books stacked on top of each other measures 1.25m. The same shelf stacked with 40 English books stacked on top of each other measures 35cm. The ...
-2
votes
1answer
38 views

Dropping the lowest number in a set lowers the mean average of the set.

So a friend of mine had her grade drop because her teacher had decided to drop the lowest grade. Is this possible or did the teacher mess up something? And if so, then how is it possible. We've ...
0
votes
2answers
37 views

Finding average using central limit theorem.

I'm have a lot of trouble trying to wrap my head around how exactly to use the central limit theorem in this question. Image a gambling casino consisting of 100 busy roulette tables. Suppose that ...
0
votes
1answer
26 views

Contraharmonic mean given harmonic mean

Given that two positive integers, $X$ and $Y$, have a harmonic mean of $6.875$, what is their contraharmonic mean. Harmonic mean is $(2XY)/(X+Y)$ and contraharmonic mean is $(X^2 +Y^2)/(X+Y)$. I began ...
1
vote
0answers
23 views

Comparing two populations

I have sampled from two separate populations, and I want to figure out which population is better. Population 1 has an average score of 84.1 and a standard deviation of 11.8. Population 2 has an ...
-2
votes
0answers
18 views

Average dividing Average

Trying to figure this out which is the better measurement. Jul 50USD Aug 150 USD Average : 100USD Jul FX : 1.5 Aug FX : 1.7 Average : 1.6 Value at Jul : 50/1.5 = 33.33 Eur Value at Aug : 150/1.7 = ...
0
votes
1answer
16 views

Harmonic Mean equation/solutioin

Here is the question: A a number x is said to be the harmonic mean of y and z if 1/x is the average of 1/y and 1/z. a. Write an equation for which the solution is the harmonic mean of 30 and 45. b. ...
0
votes
1answer
39 views

What does $h$ and $x$ represent in $2x+h$

I was asked to find the average gradient between $x=2$ and $x=5$ on the curve $y=x^2+3$. My method: Average gradient = $\frac{f(x+h)-f(x)}{h}$ $$=\frac{x^2+2xh+h^2+3-(x^2+3)}{h}$$ ...
1
vote
1answer
25 views

Is the nth root of a product of n terms used in place of the average anywhere?

In applied usage we typically take the average of values or terms which is done by summing them and dividing by the number of terms (for simple average): $$\sum_{i=1}^n \frac{a_i}{n}$$ It dawned on ...
-1
votes
0answers
32 views

Sets of 5 numbers where Mean = Median = Mode = Range = Single digit number.

http://nrich.maths.org/11281 Find all the sets of 5 numbers where: Mean = Median = Mode = Range = Single digit number I already have: -4,8,8,8,12 -3,6,6,6,9 -2,4,4,4,6 -1,2,2,2,3
0
votes
1answer
25 views

Given any combination of the average of 5 of the 6 variables, find each of those 6 variables

Suppose that there are 6 variables: (a, b, c, d, e, f), and that some magic machine gives you the average of 5 of them any amount of times, so you can find the average of (a,b,c,d,e), or average of ...
1
vote
2answers
20 views

Is that possible to get all possible numbers, if I have only an average value, max, min number & also number of numbers?

I tried to find out the all numbers or set of possible combination of numbers. But I have only the averages value, maximum number, minimum number & also have tolal number of numbers. ...
0
votes
1answer
24 views

Prove that for all n exist order in which will not any average

Prove that for all $n \in \mathbb N $ from $1$ to $n$ exist order in which will not any average of two numbers. For example $2,3,5,1,4,6$ is incorrect because between $6$ and $2$ is their average $4$, ...
2
votes
2answers
61 views

How would I apply an Exponential Moving Average to Quaternions?

I'm trying to filter positional and rotational data using an Exponential Moving Average (EMA) filter. This has worked without issues for positional data (3D vectors) but I can't figure it out for ...
0
votes
0answers
29 views

Expectation of Gaussian RV & an arbitrary function

I saw in a paper (https://www.princeton.edu/~wbialek/rome/refs/bialek+ruyter_05.pdf Eq.37) the following identity: where the <.> operator refers to a population average. No source or ...
0
votes
1answer
26 views

Why are there these patterns in these pathtraced images?

I've written a path tracing renderer for a technology class, and, while examining the histograms of the resulting images, I found a weird wavy pattern. The resultant image is the average of many ...
0
votes
1answer
28 views

Why these two average results a diferentes values?

(12 + 18 + 5) / 3 (elements) = 11,67 and (12 + 18) / 2 (elements) = 15 5 / 1 (element) = 5 (15 + 5) / 2 = 10 which one is more accurate? 11,67 or 10 ?
0
votes
0answers
11 views

Function For Calculating Average Excluding Outliers

I'm looking for a function that will let me take an average and exclude outliers. Basically something where: 1, 2, 1, 2, 7 Would average out to 1.5. Would that be along the lines of standard ...
0
votes
0answers
17 views

Calculate weighted average rate based on time

I'm trying to calculate the average consumption rate to be displayed by a computer program. Currently the average consumption rate is a cumulative average calculated by total consumption divided by ...
1
vote
1answer
20 views

Averaging data with different weights, and interpreting the results

I am trying to understand how to average certain data, interpret the result of that, and potentially convert the results to percentages. I have four categories for the data: 1: (0-50%): Not Well ...
0
votes
1answer
23 views

Which of arithmetic, geometric or harmonic mean is the most appropriate in this case?

I have a software that periodically detects tempo out of an audio signal and I would like to compute the average tempo out of all the generated values. Example: ...
0
votes
1answer
10 views

Averaging with a tolerance

I'm having some issues with trying to average some values. Lets say (for this example) that earthquakes are measured on a scale of 1-6. No earthquake can be stronger than a 6 and you want to calculate ...
0
votes
1answer
30 views

Find the average of this function

This is a basic algebraic question and probably a very simple one, but I'm a bit stuck. $$\matrix{f(x) = 1/x & \text{for x}\in [a,b]}$$ I've found that $\int (1/x)dx = -(1/x)$ The expression ...
1
vote
0answers
13 views

Calculating a moving average where the weight depends on the new value

I am attempting to write a small piece of code that tracks the both the time taken to render a frame in a single instance, and a more smoothed value that remains stagnant enough that it can be read by ...
3
votes
3answers
44 views

Convergence and Absolute Convergence of Arithmetic Mean of a sequence

Suppose $\lim_{n\to\infty}\frac{1}{n}\sum_{i=1}^n |x_i|$ exists. Does $\lim_{n\to\infty}\frac{1}{n}\sum_{i=1}^n x_i$ exist? How about the converse? My thoughts: I guess for the sequence ...
2
votes
2answers
61 views

Arithmetic Mean convergence and concave transformations

Suppose $x_i \geq 0$ $\forall i$. If $\frac{1}{n}\sum_{i=1}^nx_i$ converges as $n\to\infty$, then what about $\frac{1}{n}\sum_{i=1}^nx_i^\delta$ where $0<\delta<1$? By Jensen's inequality we ...
0
votes
1answer
17 views

Concerning averages.

Here is a simple test question: The average of 5 different integers is 33. The smallest of the 5 integers is 30. The largest of the five integers is N. How many possible values of N are there? ...
0
votes
1answer
46 views

Why is the average of the whole different to the average of the sum of the parts?

I'm a complete idiot when it comes to mathematics, so please bear with me. I have a problem. The average of the whole is different to the average of the sum of the parts. Why aren't they identical? ...
4
votes
1answer
48 views

Notation for Average of a Set?

In particular, I have some set $S = \{s_1, s_2, s_3, ..., s_n\}$ and a subset $S^\prime$, and I want to denote the average of the elements in $S^\prime$. I would generally just use ...
0
votes
1answer
15 views

On the estimation of the average of a deteriministic, scalar, real-valued function of two variables.

Suppose we have a scalar, real-valued function of two variables $F(x,y)$ where ($x$,$y$) belongs to a discrete domain $D$ of $F$, which has finite number of elements. Let $\mid D \mid$ be the number ...
1
vote
0answers
23 views

Math Average Basics, Error % calculation, and Blood Pressure.

I saw on the Olympics once when they were doing scoring for team events, that on some events the judges would take each members performance, eliminate the highest and lowest members performances, and ...
0
votes
0answers
13 views

Cumulative average of an average

I am trying to do a calculation for a stochastic oscillator on a series of stock prices in a database (SQL Server 2014). The calculation I am trying to do is as follows: Work out the lowest low for ...
0
votes
0answers
8 views

calculating a moving average rate for detecting an outbreak

I have a count for the number of occurences of a disease over a period of time. I want to set a threshold for detecting unusaul increase with a moving average. I am planning to use + 1,2,3 SD to set ...
1
vote
2answers
36 views

Adding to an average without unknown total sum

Let's say I know the following: Let A be the average value Let T be the number of values Assuming that A = 4.3 and ...
1
vote
1answer
14 views

Better Rating Result instead of Average

In my database, each item has a total_votes and total_ranking. When a user vote, I add +1 to the total votes and add its rating ...
0
votes
1answer
10 views

Continuous averaging of solar cell efficiency

I have a stream of numbers - efficiency ratio of solar cells - in range 0-100%. The efficiency is defined as (produced/expected)*100. I'm measuring the ratio every minute, and I'd like to have a ...
3
votes
1answer
75 views

What is this average called?

What is this average called? I tried Googling it but couldn't find anything about it. It's something between an arithmetic mean and a geometric mean, by which I mean you iterate both averages for two ...
0
votes
0answers
35 views

How many possibilities of sequences are there to have averages of adjecent two in the sequence will be as provided

Given: Sequence of Averages of adjecent two numbers in list i.e. (n-1) integers Output: how many non-decreasing sequences of n elements are possible? for example: Given: 2 4 Possibilities: 1> 0 4 ...
0
votes
1answer
63 views

What does this mean mathematically?

This piece of text is an explanation of item-based recommendation by Mahout (mahout-item-based-recs) Can anyone explain the meaning of 3rd line (running average means?) - for every item i that u ...
3
votes
1answer
60 views

Average distance to a random point in a rectangle from an arbitrary point

I'm interested in the mean distance between an arbitrary 2D point, $(p, q)$, and a uniformly distributed point inside a rectangle defined by the lower left and upper right vertices $(x_0, y_0)$ and ...
0
votes
2answers
35 views

Minimum Value Given Average

I am struggling with this (very embarrassingly basic) minimization problem: I have the answer, which is great, but I'm oblivious as to how to go about solving this short of using calculus. The ...
3
votes
2answers
53 views

An upper bound for an average exponentiated weighted sum of a vector from $\{-1,1\}^n$

Suppose $\mathcal{S}=\{\mathbf{x}:\mathbf{x}\in\{-1,1\}^n\}$, that is, $\mathcal{S}$ contains all $2^n$ vectors of length $n$ containing -1 and 1. I am interested in the following average: ...
0
votes
1answer
19 views

Covering deficits with values with different weights

SO I have a couple of assessments with specific weights as follows: Assignment 1: 5% => Mark 60% Assignment 2: 5% => Mark 53% Assignment 3: 5% Assignment 4: 5% Test 1: 30% => 47% Test 2: 30% ...
1
vote
1answer
51 views

Why average until $n-1 \times n \simeq \sum^{n-1} + avg_{n-1}$?

I'm newbie in math and I want to understand it: let $A = \{a_1,...,a_n\}$ why $$(\frac{1}{n-1}\sum_{i=1}^{n-1}a_i)n \simeq (\sum_{i=1}^{n-1}a_i)+ (\frac{1}{n-1}\sum_{i=1}^{n-1}a_i)$$ Exists any ...
0
votes
1answer
20 views

Selecting denominator for relative error margins

When looking at this page: http://floating-point-gui.de/errors/comparison/ there are values a, and b that are being compared ...
0
votes
1answer
22 views

How do I Adjust Dynamic Weighted Averages?

I am trying to create a formula in Excel that tries to create a weighted average score for a person. The only problem is that sometimes one or two of the components of the weighted average may not be ...