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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6
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0answers
246 views

What's the average distance between two discs in the plane?

Consider two discs in the plane of radius $r$ and $s$, with centers separated by a distance $l$. If we choose a point uniformly at random from each disc, what is the expected distance between the two ...
4
votes
0answers
402 views

Average transformation matrix?

I have several estimates of the transformation matrix between two planes and some values that give some indication of the error involved in the estimate. How can I use this information to gain the ...
3
votes
0answers
114 views

Finding a summarizing vector for average angle calculation

Let $L$ and $R$ be two bags of positive vectors such that all vectors have length $k$. Define the distance $d_{avg}$ between the bags as the average pairwise angle between the vectors. Is is possible ...
3
votes
0answers
51 views

Find spikes in data

I have some datasets and I need to find spikes in them. Imagine the data looks like trading data. If the spike is big enough, I need to log it, otherwise, proceed in the analysis. I tried with a ...
2
votes
0answers
34 views

Flat Tax vs. National Income Tax Average

If the national income tax average under a progressive system is 30%, will tax revenue change if the progressive system is changed to a flat tax also at 30%? In other words, if the mean average ...
2
votes
0answers
33 views

Are these two approaches to calculating return rate mathematically consistent?

I have coded two C# programs, which use two different approaches to evaluate the outcome of a certain casino-style game (casino-style in the sense that the user pays points to take a turn, and ...
2
votes
0answers
63 views

Compute average and maximum value of a field over a streamline

I'm working on a code solving a set of PDEs. I have a vector field, $\vec{v}(x,\theta,z,t)$ (it's a velocity) and a scalar field, $c(x,\theta,z,t)$. I have a $2\pi$-periodicity in $\theta$. The ...
2
votes
0answers
73 views

Have averages, need variance

I have a large spreadsheet, generated by a colleague, that contains the results of $E$ experiments. For each experiment, he calculated the average of $M$ measurements. I need the calculate the ...
2
votes
0answers
28 views

Inference the time a process would take depending on the number of threads

I have several datasets consisting on: Number of threads n Start process time t1 Stop process time ...
2
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0answers
587 views

How can you calculate actual values when all you have is rolling averages?

Let's say you have a set of data that is rolling 6 month averages of the actual monthly data. Good data collection would mean you saved the actual values and then calculated the rolling averages, but ...
2
votes
0answers
261 views

Exponential average of logs

I'm working on a sound recognition algorithm where an "exponential moving average" is used for "adapting" to sound levels. It turns out that taking an average of logs works better than simple sums ...
2
votes
0answers
507 views

How can I compare two averages of imperfect measurements, with their std. deviations?

I have a process by which I measure the times it take to do something, (run some code), and this time varies, a lot. I'm trying to optimize this code, making small changes that sometimes have small ...
1
vote
0answers
18 views

Approximate values from point groupings

Say I am given a set of values: \begin{bmatrix}0.9&1.1&1&1.95&2&2.05&2.95&2.95&3.1&3\end{bmatrix} Is there a way I can get the 'center' or 'average' values 1, 2, ...
1
vote
0answers
27 views

Averaging speeds

I read the answer to this question: http://stackoverflow.com/questions/34794664/how-should-i-calculate-the-average-speed-by-road-segment-for-multiple-segments/34795821#34795821 Can anyone please ...
1
vote
0answers
23 views

Advise on Weight Function for statistical analysis needed

I'm doing a statistical analysis of an experiment I'm conducting, and right now I'm trying to define a proper methods for data mining. Please take a look at my problem: I'm doing a user research ...
1
vote
0answers
16 views

Calculating Weighted Averages – selecting a correct numerical scale for several variables

I have the following variables that i am going to use to calculate a weighted average: Variable Format Weight applied (out of 1) A Percentage 0.2 B Percentage ...
1
vote
0answers
18 views

What kind of time series do I need?

I am trying to optimize a list of websites on which to purchase banner advertising using the following setup: For each banner ad impression I buy I am charged $0.001. When my ad is clicked it ...
1
vote
0answers
39 views

Matlab, Extracting Particular Values from an Excel File

If I have a table of values in Matlab ( here I have a 40k rows, and about a dozen columns), how can I read only particular values from each row? My goal is to extract some of the values from each row, ...
1
vote
0answers
22 views

Averaging Models in Excel

I am working in Excel and have two sets of data points that come up with a percentage for the likelihood of a recession. I am wondering what the best strategy would be to combine these data points? ...
1
vote
0answers
36 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 ...
1
vote
0answers
42 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 ...
1
vote
0answers
161 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 ...
1
vote
0answers
321 views

About Bayesian formula and rating system

I'm building a scoring system with score from 0 to 5) and I would like to sort products according to the number of reviews and their scores. After some research on the Internet I have found two ...
1
vote
0answers
42 views

Average minimum distance

Let $\mathbf{u} =\begin{bmatrix}u_1 & u_2 & \dots & u_N \end{bmatrix}^T$ and $\mathbf{v} = \begin{bmatrix} v_1 & v_2 & \dots & v_N\end{bmatrix}^T$. All the elements of ...
1
vote
0answers
117 views

Finding possible numbers to yield a certain arithmetic mean (average)

I'd like to know how I could find the possible numbers to yield a certain average number (arithmetic mean), given that: the arithmetic mean will be calculated from 20 integer numbers, each having a ...
1
vote
0answers
111 views

Deal or No Deal: Arithmetic, Median or Geomtric mean?

I'm trying to decide which type of mean is best to use when playing Deal or No Deal (in terms of comparing it with the Banker's offer). I realise the standard answer would be the arithmetic mean, but ...
1
vote
0answers
26 views

Estimator of Absolute Error?

Given $X \sim B(n, p)$, we know that $\hat{p} = X / n$ is the obvious estimator for unknown parameter $p$, and the following quantity $$\frac{\hat{p}(1-\hat{p})}{n-1}$$ has the property that its ...
1
vote
0answers
1k views

Bar Mean vs Bracket Mean

I know that the standard representation for the average of a data set: $$ \bar{x} = \frac{1}{N} \sum_{i}^N{x_i} $$ I have also ran into an average denoted as $\langle x \rangle$. This notation is ...
1
vote
0answers
37 views

Is $x_1^{\alpha_1} + \dotsb + x_n^{\alpha_n}\geq x_1^{h/n}\dotsb x_n^{h/n}$ an example of power means?

I learned here that there is a relation between weighted means of the form $x_1^{\lambda_1}\dotsb x_n^{\lambda_n}$ and $(\lambda_1 x_1^r + \dotsb + \lambda_nx_n^r)^{1/r}$, namely that the former is ...
1
vote
0answers
63 views

Difference between $\frac{1}{n} \sum_{i=0}^n \frac{b_i}{a_i+b_i}$ and $\frac{\sum_{i=0}^n b_i}{\sum_{i=0}^n a_i + b_i}$

Consider scenario like this: each user can add movies. each user can rate movies he added. I want to know how many movies average user has unrated (as in average percentage). Let's translate this ...
1
vote
0answers
68 views

How to measure the time-decayed rate of independent event

I have events arriving in a software system at a variable rate. Imagine these events are, say, hits on a website. I'd like to periodically report on the rate of arrival of events over a number of ...
1
vote
0answers
59 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 ...
1
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0answers
41 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 ?
0
votes
0answers
20 views

Average number of $5$-card draws before all $52$ cards in a deck are drawn.

So an interesting question was brought to me today and I'm not sure how to formulate the equation to answer it. A person draws $5$ cards from a deck, writes the cards down, puts the cards back in the ...
0
votes
0answers
7 views

Multiple server queuing model

I have come across the following problem in one of my courses: Let's suppose a patient in a hospital is waiting to be picked by one of the two doctors available. The time till a new pacient arrives ...
0
votes
0answers
10 views

Weighted average of unit vectors

I am trying to determine the yaw (z) axis of a vehicle given a bunch of sensors, each of them subject to different kinds of error. This means I get a bunch of unit vectors for the z axis, expressed ...
0
votes
0answers
16 views

How to find the best-case and average-case number of comparisons performed by a comparison tree?

So I'm reviewing some material before a midterm tomorrow and I came across this question: ...
0
votes
0answers
31 views

Calculating the average case complexity for finding the maximum number in an array

Algorithm: Given a non empty array with $N$ Numerical values, the algorithm finds the location LOC and the maximum value MAX of the largest element of DATA. Initialize K:= 1, LOC:=1, ...
0
votes
0answers
51 views

Working out averages for goals scored per football game

If for example I had a sample set of 11 football games. Of those 11 games, there were a total of 8 goals. So I can work out the average goals per game by ...
0
votes
0answers
40 views

Time series analysis, moving-average model, ARMA model

I'm reading documents about time series analysis, including Autoregressive–moving-average model, Moving average model, Wold's theorem, etc. The notation MA(q) refers to the moving average model of ...
0
votes
0answers
28 views

Is exponential decay a moving average filter?

I learned that a moving average filter is an FIR filter that gives the average of $N$ previous inputs, like this: $y_n = \sum_{i=0}^{N-1}\frac{x_{n-i}}{N}$ As a simple extension, it might be some ...
0
votes
0answers
32 views

Calculating Average “Productivity”

Let me apologise in advance if my terminology is incorrect or if what seems logical to me is completely nonsensical. I am an analyst without a mathematical background and have tried to self teach off ...
0
votes
0answers
10 views

Probable minimun of a set having only Maximum, Average and the number of values

I have a data set in which I am given the number of values, the average and the max, how can i work out the probable min value? Thanks
0
votes
0answers
27 views

What type of function is F?

Suppose that $ X= \{(x_1,d_1),(x_2,d_2),...,(x_n,d_n)\}$ where $x_i$ for $i=1,...,n$ are variable and $d_i$ for $i=1,...,n$ have constant values, then we define: $$F(X)= \sum_{i=1}^{n}(\frac{ x_i} ...
0
votes
0answers
28 views

Calculating percentage of range of values given total set members and average (review ratings)

Given the total number of members in an unknown data set, with values ranging from a minimum of 1 to a maximum of 5, is it possible to determine the probable percentage of values that fall within a ...
0
votes
0answers
11 views

Calculate portfolio weighted averages - smoothing curve

I'll first off apologize for not knowing how to ask this question properly, but I just can't come up with the right words which is likely why I can't find an answer. I have a fairly simple portfolio ...
0
votes
0answers
20 views

Weighted average of slope

I'm trying to find the weighted average of a temperature increase in a vessel. So, essentially the weighted average of a temperature over time. I'd like some input if this equation gets me what I'm ...
0
votes
0answers
13 views

Weighted rating value

I have a database consisting of clubs and its ratings people have provided them with. Currently, I am performing an average of the ratings based on a club and then sorting these averages ...
0
votes
0answers
26 views

Which is the default Standard Deviation Formula

I have to implement a test from research paper which says: As for testing criteria, standard deviation or min-to-90th percentile ( ) of large packets (1500 B) can be effectively used to find the ...
0
votes
0answers
6 views

Graphical Representation of the Risk over different aspects

I am having the Risk Factors which are from more than one assessment. want to show the Risk of the all assessment for year 2015 or any Month of 2015. all risk factors can be the part of any of the ...