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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1
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2answers
115 views

Calculating new vector positions

I'm using the following formula to calculate the new vector positions for each point selected, I loop through each point selected and get the $(X_i,Y_i,Z_i)$ values, I also get the center values of ...
1
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1answer
198 views

Calculate vector position

I'm trying to calculate & move vertices to their average "radius" and form a circle from these new positions. Example: I have 8 vertices selected, I have a little script in Maya that will iterate ...
2
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3answers
4k views

Standard deviation of the weighted mean [duplicate]

How do you find the standard deviation of the weighted mean? The weighted mean is defined: $\bar{x}_w = \frac{\sum{wx}}{\sum{w}}$ The weighted standard deviation (since it is not specified, I take ...
0
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1answer
1k views

Average Slope of 4 Slopes

I want to calculate tha Average Slope of 4 Slopes, but Im not too sure if this will require me to calculate the Average error when I do calculate the average of the 4 slopes. Im obviously calculating ...
2
votes
1answer
60 views

What is this physics simulation formula doing?

I have encountered a piece of code that performs a physics simulation of a moving projectile. I'm trying to understand what the mathematical basis is for a bit that looks like this: $$ d_1 = f(x) $$ ...
1
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2answers
136 views

Merging/averaging percentages

This may be a very simple question, but I'm not even sure what the correct terminology is for the procedure I am trying to do so I wasn't able to find anything else here... The scenario is that I'm ...
1
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1answer
76 views

Why 1 / (average of series) $\ne$ average (1 / series)

I have series of two stocks prices. Let's say that stock 1 has prices: $A_1$, $A_2$, $A_3$, $A_4$, ..., $A_i$ (where $i$ is time) And stock 2 has prices: $B_1$, $B_2$, $B_3$, $B_4$, ..., $B_i$ ...
0
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1answer
276 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 $x_1$, $x_2$, ...
0
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1answer
85 views

Most Probable Average Marks

There is a class of 40 students. A professor conducted a quiz on which consisted of 10 Multiple Choice Questions. Each question had 4 options, out of which only one is correct. Each question carried 1 ...
0
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2answers
378 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 ...
0
votes
2answers
284 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. ...
0
votes
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.. ...
1
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1answer
181 views

Intuition calculating average price change

Given two products p1 and p2, each with a price per single unit and an amount per year. The question is to calculate the average change in price for both products combined. ...
1
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0answers
47 views

Deconvoluting linear combinations of unknown distributions

Summary I am trying to deconvolute the distribution $T(x)$ of a population's $x$ parameter into sub-distributions ($P(x)$, $Q(x)$, $R(x)$ ...), of which I don't know the form (only that they have ...
4
votes
5answers
199 views

what is the argument for not using the average of an average?

I want to disprove someone's calculation of percentage of cash sales for a year by taking summing percentage of cash sales by month and dividing by 12. I sense the correct way is to take total cash ...
1
vote
2answers
172 views

Average limit superior [duplicate]

Let $\mathcal{l}_\mathbb{R}^\infty$ be the space of bounded sequences in $\mathbb{R}$. We define a map $p: \mathcal{l}_\mathbb{R}^\infty\to\mathbb{R}$ by $$p(\underline x)=\limsup_{n\to\infty} ...
2
votes
0answers
25 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
votes
3answers
365 views

Averaging the values of $\cos x$ over one period

I'm calculating the average value of $\cos x$ by dividing the period $[0,2\pi]$ into ten intervals which means that I should be looking for the average of 11 results. What I get is approx. 0.09. The ...
1
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1answer
64 views

Calculating expected value

Here is the problem. In a game(shown below) with the marker in the center on each turn the marker moves to a neighbouring region with all positions equally likely and the player collects the cash ...
0
votes
1answer
87 views

finding average price of two lots of shares

Sorry, not a math guy, this might be an overly simple question for the lot of you, but it's a calculation that I'll have to do a lot possibly, so please show me the best way to do it. If I have $1265$ ...
3
votes
1answer
83 views

How do I average a new number into an established percentage if I know the number of items?

This seems like something I should be able to do but I can not for the life of me figure it out. I'm writing a program to calculate an average score; let's say that my data looks like this. x = ...
1
vote
1answer
38 views

Generating statistics from data samples, that are of snapshots.

My question is part math part computers but I need more of the math answer then a computer answer. I am going to be grabing snapshots of a moment of time on how a computer is performing. Because of ...
1
vote
2answers
542 views

How can I find the average y value of a function on a given domain?

Lets say that $f(x) = (10 - x)\ln x$. Over the domain: $1 ≤ x ≤ 10$. How can I find the average value of $y$ over this domain and what is that value?
1
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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: ...
1
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1answer
129 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 ...
1
vote
1answer
102 views

Derivative of a 'weighted average' of decreasing fractions

I'm having some trouble showing the following statement (which intuitively seems to hold): Suppose I have a series of fractions indexed by $i$ , each of them a function of $N:f_{i}\left( N\right) ...
1
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1answer
191 views

Minimum Numbers to find the given average.

Average score of the player (sum of scores in all the games / no. of games) is given. How Can we find the minimum number of games the player should have played to achieve that average. scores are non ...
2
votes
1answer
187 views

Average delta value of a sequence of $N$ $8$-digit numbers

Given a sequence of $N$ $8$-digit numbers, how to calculate the average delta value, thanks.
0
votes
0answers
496 views

Averaging equation?

Is there any name for following averaging equation and how does it work? $$ y_{i+1} = (1-\alpha)\times y_i + x_i $$ I'm using it to average a signal, but I'm not sure am I interpreting the results ...
1
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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 ...
2
votes
1answer
157 views

Average number of rolls of die to see each side at least once [duplicate]

Possible Duplicate: A Question About Dice You have a weighted n-sided die. Every side of the die is weighted differently where side n1 has a weight of w1, n2 has a weight of w2, ... ...
4
votes
2answers
1k views

What is the average of rolling two dice and only taking the value of the higher dice roll?

What is the average result of rolling two dice, and only taking the value of the higher dice roll? To make sure the situation I am asking about is clear, here is an example: I roll two dice and one ...
6
votes
4answers
1k views

Average bus waiting time

My friends and I were "thinking" yesterday in the pub about the following: if a person is standing on a bus stop that is served by a single bus which comes every p minutes, we would expect the average ...
1
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1answer
1k views

Average proportion for proportions with different denominators

Say I have an experiment in which subjects are asked to respond to some stimulus. Their responses are transcribed and coded, first as "Valid/Invalid", and then for the valid responses, ...
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votes
2answers
1k views

How to calculate MEAN of exponential distribution?

$ f(x) = \begin{cases} \frac15 e^{(-\frac15x)}, x>0 \\ 0, \text{elsewhere}\\ \end{cases}$ How to calculate $E[(X+5)]$ and $E[(X+5)^2]$ ? Thanks a lot.
0
votes
3answers
448 views

How do I find the average of a section of a curve?

I've done some research already and discovered that the formula I need to do this is $$\frac{1}{b-a}\int_a^b f(x)\;dx$$ With $a$ and $b$ being the start and end points of the section of curve I want ...
2
votes
2answers
239 views

Least Squares Fit

So here's the question: Given a collection of points $(x_1,y_1), (x_2,y_2),\ldots,(x_n,y_n)$, let $x=(x_1,x_2,\ldots,x_n)^T$, $y=(y_1,y_2,\ldots,y_n)^T$, $\bar{x}=\frac{1}{n} ...
2
votes
1answer
3k views

Average, standard deviation and min/max values

I'm analzying a computer science paper and just found in the experimental setup the following statement: Average (standard deviation) of number of files per peer: 464 (554) Min - max number of files ...
3
votes
2answers
1k views

Average Distance Between Random Points in a Rectangle

My question is similar to this one but for rectangles instead of lines. Suppose I have a rectangle with sides of length $L_w$ and $L_h$. What is the average distance between two uniformly-distributed ...
0
votes
2answers
156 views

How can i solve this problem about averages?

The average (arithmetic mean) bowling score of $n$ bowlers is $160$. The average of these $n$ scores together with a score of $170$ is $161$. What is the number of bowlers, $n$? I tried this: $$X'*n ...
0
votes
1answer
42 views

Formula for normalising with respect to average

I have a 5*5 grid (as in the figure). At each point there are 5 dishes of varying numbers of bacteria. I'd like to write a formula which calculates the average of these 5 and then divides by the ...
0
votes
2answers
91 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.
1
vote
2answers
75 views

Finding one value from a mean.

7 boys have a mean height of 1.80m. Peter joins the boys and now the mean height is 1.75m. Find Peter's height.
0
votes
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 ...
3
votes
3answers
215 views

Erased number?

A set of consecutive positive integers starting with 1 is written on the board. A student came along and erased one number. Average of remaining numbers is 61 15/20 . What was the number erased
4
votes
1answer
1k views

How to calculate an overall 5 star rating based on other weighted 5 star ratings

I have these 3 ratings. I want to combine them to produce an overall rating out of 5. The overall rating can be a float, so no rounding is necessary, but it cannot be negative. I'm just not sure ...
0
votes
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 ...
0
votes
1answer
150 views

Continuously sampled event: Estimating the value of a future data point, based on past measurements and their tendency

Problem I'd appreciate some ideas on how to define a formula to estimate the value of a future data point for a continuously sampled event, based on past measurements and their tendency. At any ...
0
votes
1answer
73 views

How to calculate variance on spending?

My maths is a little rusty, but I understand how to calculate variance in general. A colleague asked me if I knew how to calculate the percentage variance on budget spending. Given this example: ...
0
votes
0answers
177 views

Need algorithm to take “max” of scores, but with “quality” weighting

I have an application where I get a small number of scores from medical tests (the same test repeated a few times) and I need to combine them. Normally the highest score would "win" in this ...