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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1answer
147 views

Calculating average customer turnover

I am currently coding a script which displays data for a company intranet. I am stuck with a question that seemed pretty simple, but turned out to give me headaches. We have the following scenario: ...
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1answer
131 views

Estimating a sample mean using sub-sample means

we collect a lot of data on a daily basis via an API, and part of this data includes fields that represent sample means. Specifically, we get provided with a sample mean and the sample size, lets call ...
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1answer
68 views

averaging STDs vs. calculating a single STD

I have a set of data points. I extracted the Standard Deviation for the whole set, and also extracted STDs for a partition of the points where each element of the partition has at least two points. I ...
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0answers
54 views

Taking averages

Suppose I have a function $f(\theta)$ that is a function of the angle $\theta\in [0,2\pi)$. Why is the average of $f$ over a large collection of randomly oriented objects: $$\int f(\theta)\sin ...
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29 views

Dynamic Light Scattering

In DLS does the combination of the Time Average and Ensemble Average give a better statistical average than the results shown by each case considered separately ?
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1answer
48 views

Variant of the modal average

I know that there are variants of the arithmetic mean and the median that are applicable to three dimensional data (centroid and medoid), but have not been able to find such a thing for the modal ...
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2answers
55 views

Average of percentage of 2 numbers.

If I have 24081 items sold at 45% off. and 11386 items sold at 60% off. What is the average percent off for all items sold? Thanks for your help in advance! Craig (This is not homework :) )
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78 views

How to get the average of $a$, $b$ when all you know is the average of $a,b,c$ and the value of $c$?

I need to figure out some averages for some javascript I'm writing. The data I have is: I know the average of $a$, $b$ and $c$. I know the value of $c$. I do not know the values of $a$ and $b$. ...
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144 views

Getting Average

How excatly do I calculate the average? Can somebody explain step by step process of how to get an average? If I have an array of numbers (5, 3, 4, 3, 1) and so on. And I need to get the average of ...
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44 views

Average Proofs, where $n\ge 2$ is greater than the average of real numbers

Prove that at least one of the real numbers $a_1; a_2;... a_n,$ where $n \ge 2$, is greater than or equal to the average of these numbers. I'm stuck on how I am supposed to prove this. Honestly ...
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143 views

Effect of removal of numbers while calculating average

My question is , lets say we have the numbers 1,2,3,.....,n numbers . 2 consecutive numbers are removed. The avg of the numbers after the removal of numbers be m let the numbers removed be k,k+1 ...
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5answers
405 views

Is this a weighted average/percentage problem?

Let's say a Marketing company has a total turnover of 10000 \$ There are 3 salesmen A,B,C with the following turnovers A = 2000 $ B = 3000 $ C = 5000 $ Now, ...
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1answer
284 views

Working with average numbers and finding unknown variables?

There is this question I was approached with and I am absolutely stumped on where to even begin to solve it. It goes like this: Based off the following 4 equations, find the average of $x_1$, $x_2$, ...
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2answers
93 views

given average score,find the selected numbers

Suppose average score of 46 scores selected from 1,2,3,4,5 is 1.65.Is there any way to find out which are the scores that are selected.
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2answers
42 views

Computing the average difference in a list of numbers

I have a list of numbers 280, 449, 689, 959, 1360, 1740, 1139 so there is between 289 and 449 is a distance of 169 and then between 449 and 689 a distance ...
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3answers
42 views

Help with question about Normal distribution

The heights of people at some city is $N(\mu,\sigma^2)$. 25% of the people are above 176 cm. and 20% are below 165 cm. How do I found $\mu,\sigma^2$? We choose randomly a group of 100 people. What ...
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1answer
37 views

Average value calculation

A company has 2 mines: A and B. The production per person in mine A was 22,6 tons last year, and 27,9 tons in mine B. Last year 60% of the total production came from mine A. The question is the total ...
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2answers
17 views

Is there a formula for finding the series of numbers based on an average.

So I am working on a program that does a scrolling effect. the image is 1200pixels wide, and each time it scrolls, it should move an average of 2.67 pixels. However I am using a function that does not ...
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3answers
87 views

Should you average or add together daily bank balanace averages?

I work in the finance field and I am looking at average balances on bank statements balances. When I have more than 1 bank statement I need to reflect the overall average balance between the ...
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2answers
68 views

Bringing numbers in a set closer together

I'm trying to express the relative scale of items compared to an "average" scale for all items in the set. This produces values like { 0.5, 1.8, 0.3, 1.2 ... } I then wish to use this number to ...
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2answers
1k views

What is a simple formula to interpolate 2 unknowns between 2 knowns?

What is a simple formula to find 2 intermediate values between 2 known values? f(1)=a, f(2)=?, f(3)=?, f(4)=b If there would be only 1 unknown, then it would be ...
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2answers
603 views

Weighted average of two frequencies

This should be really simple but I'm getting stuck and I'm probably extremely dumb.. I know that a machine receives two kind of parts: Type 1 -> with frequency 50 per week, each one is processed for ...
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1answer
26 views

Probability static area is greater than variable area

I have a rectangular section of constant height and length and I choose a random starting point anywhere along its length. From the randomly chose starting point, I first add ...
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1answer
18 views

Average value for multiple integrals

If there is a function $f(x,y)$ and we want to find the average value over a region $R$ defined by $0<x<1$ and $0<y<x$, how is that computed? I know that it would be something like this: ...
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1answer
34 views

Help with finding the arithmetic mean of all the radii from the center to the edge of an ellipse?

So far I approached this problem computationally, I decided to take all the radii add them up, by distance formula, then divide by the number of radaii. To make the distribution even, I rotated the ...
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2answers
85 views

Calculating average value of points over a period of time

I have several values plotted over a period of time on a line graph. The length of time between values is not uniform (i.e. one value could be 3 days after the one before, which itself could be 2 ...
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1answer
23 views

Likelihood across multiple averages… Sorta

Hopefully my title isn't misleading... i'm not sure what this math problem is called, making searching for the answer quite difficult. Maybe someone can tag this question appropriately if you know the ...
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1answer
59 views

Fast way to recalculate average and standard deviation as new values arrive

Say I have a stream of values arriving all the time, and I want to get the average and standard deviation of only the last $n$ values. If I already have the average $V$ for values $v_1, ..., v_n$, ...
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1answer
130 views

find the average of a student [closed]

Five students in a closed room want to find average of their exam scores without revealing their personal score to each other. How can they do it? Hint: they can write something on paper and pass it, ...
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2answers
37 views

Inverse Percentage.

Sorry for asking this foolish question. Here is the data i have. I purchased the product as $5 and additional fee is 2%. So Here is the total dollor ...
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2answers
45 views

Average and aggregate values with a distribution function

I'm reading an economics paper and I'm trying to understand if a statement made by the author is an assumption or the consequence of a previous definition. The part I don't understand is the ...
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1answer
93 views

I have a mean and a desired range for a normal distribution, how do I discover what standard deviation I need?

I have a mean and a desired range for a normal distribution, how do I discover what standard deviation I need? I may not be using the correct terminology so here's a graph: Based on this, if you ...
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2answers
140 views

Calculate the average sales per day in 2010.

In 2005, Company K was 730 000 units of the car market. Total sales is 50% of the total cars sold in 2010. Calculate the average sales per day in 2010. Calculation: 1) 50/100 x 730 000 2) 730 000 x ...
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1answer
107 views

average/weighted average within Excel

5 star 128 4 star 17 3 star 10 2 star 2 1 star 14 Average stars 4.42 How many more 5 stars would I need to get ...
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2answers
381 views

How to recognize ellipse/ellipsoid from random points? UN-weighted average?

Suppose we are getting random points in 2D (or 3D) which tend to be on ellipse (or ellipsoid). We can't guarantee points are uniformly distributed over ellipse (ellipsoid surface). The task is to ...
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2answers
286 views

Average percentage of percentage

I ran a survey on my website where users marked a checkbox for what % they did X. Something like this. ...
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1answer
56 views

How to average numbers with high standard deviation

I have a set of n numbers that I need to review and come up with the closet average. The set of numbers may or may not have a high standard deviation. Below is an example... Set of numbers.. ...
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1answer
35 views

Finding average of a sample with single piece of data

Is there anyway possible to guesstimate/estimate the average of a sample if you know just one of the sameple and its position when all available samples are arranged ascendingly and total number of ...
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1answer
185 views

Calculating average of word problem

I was preparing for a standardized test and came across the following problem: During a closeout sale 30 suits are sold at \$60 each.The price is the reduced to \$50 each and 20 suits are sold. At ...
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1answer
146 views

Calculate average time

I have a huge list of times and would like to calculate an average or typical time. If I would just use the median (or other "normal" types of calculating an average), for example 23:59 and 00:01 ...
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1answer
2k views

How do I calculate weighted mean with negative weights?

This might be very trivial for you guys. If : I buy 2 oranges for 5 dollars each then I buy 3 oranges for 6 dollars each and then I sell 3 oranges for 4 dollars each How do I calculate the average ...
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1answer
19 views

Calculating weighted score of test

I have a test containing questions with 3 levels of difficulty: ...
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1answer
28 views

Find average stream velocity over a cross-section of a cylinder, given $v(r) = k(R^2 − r^2)$

I'm doing integration homework and a question that I am not sure how to approach popped up. The velocity (in centimeters per second) of blood r cm from the central axis of an artery is given by ...
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1answer
43 views

Calculating average over a year

I'm trying to calculate the average count of employees for a group of companies. I need to exclude months where a a company had no employees. Please verify that my approach is correct. ...
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1answer
30 views

How do I “recalculate” a median number?

I'm not sure how to explain the question, so I'll do it by an example. The median age in some country is 41.7. 50% is younger than 41.7, 50% is older. How would I calculate the percentage of the ...
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1answer
25 views

What ratio of students in a 20-student class with total average of 17.06 got at least 17?

The maximum score is at most 20. The class has 20 students. For math exam the average of the whole class is 17.06. How many per cents of the class got at least 17 out of 20 in the exam?
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1answer
16 views

How should I calculate weighted average in this case?

If there is a product, whose price depends on its quality, and these price values are: [0.6; 1.1; 1.3; 2.0; 4.2; 21.6] Lets assume that there is some kind of a lottery, and I can by a ticket for it ...
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2answers
36 views

average and total average

why is it when I get the average of the column "per hour", it's different from the total?
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1answer
29 views

Mean squared [X] or Mean [X] squared?

If I have two functions, as below, which one is "Mean [X] squared" and which is "Mean squared [X]"? Would I be correct in saying the former is number 1 and the latter is number 2? Thanks in advance ...
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1answer
18 views

Count if there are more smaller or larger number in a result made of multiple Xs?

Firstly, I am not a math pro or something. So far I was able to use math for my needs, but now I am at my wits' ends. Here is the deal. These things are known to me: ...