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

learn more… | top users | synonyms

1
vote
0answers
29 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
14 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
10 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
48 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
12 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
41 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
64 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 ...
4
votes
1answer
70 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
57 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
20 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
52 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
24 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 ...
0
votes
5answers
59 views

Confusion (Averages)

I'm getting insanely frustrated with this. The average of $6$ numbers is $4$. A seventh number is added and the new average is $5$. What is the seventh number? How do I solve this algebraically? $6 ...
0
votes
1answer
15 views

Equation for the average of a known quantity of numbers

How would one express this in the form of an equation? The average of 500 numbers, each of which are between 2 and 50, is 7.5 And can it be graphed?
0
votes
3answers
41 views

Get the minimum value for multivariable

I need a way to calculate the very minimum of each variable for a grade average. Each grade variable have a weighing percentage (I don't know if it's the right term) The weighing sum must be the ...
0
votes
3answers
73 views

There are two cars…

Let's imagine a $6000 km$ stretch of road. Now, there are two cars $A$ and $B$, each with average speeds of $100km/h$ (for $A$) and $250km/h$ (for $B$) respectively. If $A$ is given a headstart of ...
13
votes
3answers
240 views

If my average speed is 50 mph, is it better to go 10% faster or 5 mph faster? (These are not the same)

BACKGROUND Suppose we have a journey between A and B where different sections of roads have different speed limits and our average speed is 50 mph. If when I repeat the journey I travel 10% faster ...
0
votes
1answer
46 views

Incremental averaging (different case)

I've seen the integer version $$m_n = m_{n-1} + \frac{a_n-m_{n-1}}{n}.$$ But how do I calculate it where there are amounts, which is $$A=[3, 5, 4]$$ and the corresponding quantities $$Q=[1.5, 2.5, ...
0
votes
1answer
57 views

alligation problem

Ravi lends Rs 3600 on simple interest to Harsh for a period of 5 years. He lends a part of the amount at 4% interest and the rest at 6% and receives Rs. 960 as the amount of interest. How much money ...
1
vote
3answers
47 views

Mean of a vector

Be a set of numbers $v=(a_1, a_2, \ldots, a_n)$ I want to form the following average vector $\mu = (\frac{\sum a_i}{n}, \frac{\sum a_i}{n}, \ldots, \frac{\sum a_i}{n})$. If I do it iteratively step ...
1
vote
1answer
72 views

Maximum and minimum average question

During a cricket match, India playing against NZ scored in the following manner: Partnership | Runs scored 1st wicket | 112 2nd wicket | 58 3rd wicket | 72 4th wicket | 92 5th wicket | 46 6th ...
1
vote
1answer
57 views

problem in understanding overall change in average

The average weight of 5 men is decreased by 3kg when one of them weighing 150kg is replaced by another person. This new person is again replaced by another person whose weight is 30 kg lower than the ...
0
votes
0answers
27 views

higher order schemes or curvature to be smoothed

I want to calculate the radius of curvature of a meandering river. I have done a first estimated using a tool in arcgis. These are the results. The values of -99999 are recorded for points of no ...
1
vote
2answers
39 views

Estimated wait time for a library book

A library has 20 copies of a book that circulates for 3 weeks. All copies are out and there 40 people on reserve ahead of me. How do I estimate the wait time?
0
votes
1answer
33 views

Basic algebra problem for weighted averages

This question has me completely stumped for some reason, I would appreciate a bit of help. If you have 20 pounds of coffee for $1.80 a pound And then add X amount of coffee for $1.44 a pound How ...
0
votes
1answer
25 views

Mean of a discrete function

I have a set of finite variables (~20) which when plotted are forming a decaying exponential function. I want to know is there a better way to calculate the average of this function than by just ...
-1
votes
1answer
47 views

What is the meaning of |⋯| notation for an index subset?

I am currently working on a research project. In the attached image what does the capital $|I|$ and $|J|$ mean ?
0
votes
1answer
36 views

Average value of function that converges?

I have a function $f$ that converges to a value: $$ f(x) = 1−s−A \beta ^ x $$ Where $A \in \mathcal{R}$, and $0< \beta <1 $, $0< A <1 $ I want to get the average value of for $ x > ...
0
votes
1answer
27 views

Average of Numbers

Consider the following problem: if $a \leq b \leq c \leq d \leq e \leq f \leq 101$ and if average of these(a,b,c,d,e,f) numbers is 100 then what could be the least value of a?
0
votes
0answers
12 views

Averaging of a product of fast oscillating function and slow oscillating one

Let's have a product of fast oscillating function and some slowly oscillating function: $$ F(\mathbf r) =f(kz)g(\mathbf r), \quad f(kz) = cos^{2}(kz),sin^{2}(kz). $$ I want to average this quantity ...
0
votes
1answer
24 views

How can I understand a formula written in this format. I am a beginner.

$$\bar{l}(\mathcal{P},\mathcal{L}) = \sum_{j=1}^n p_j l_j$$ I have just started studying this module and it describes the equation as the the average length of the code. Can you please break ...
0
votes
1answer
28 views

In data compression this equation describes the 'average length' of the code. Can someone please explain?

$$\bar{l}(\mathcal{P},\mathcal{L}) = \sum_{j=1}^n p_j l_j$$ I have just started studying this module and it describes the equation as the the average length of the code. Can you please break ...
0
votes
2answers
17 views

What is the Term for the Center of Mass Equation Structure

What is the term for the generic structure of this form of equation: SUM(Mi * Xi) / SUM (Xi) It is the same as the center of mass calculation.
0
votes
3answers
59 views

Average speed question of a car on an oval track

On an oval track, a car averages $30$ M.P.H. (miles per hour) for the first lap (a lap is $1$ mile around the track). At what average speed must that same car drive the 2nd lap on that same track so ...
1
vote
1answer
16 views

Simplifying an indefinite integral representing the calculation of an average

I have an equation for a term $z_i$: $$ z_i = \ln\frac{a_iR+p_i}{T_o* tan\theta_i } $$ This represents a value in a grid, at location $i$, with the grid representing a geographic area. To get the ...
2
votes
2answers
31 views

A Percentage of Averages

A company brags about the speed of their service, "75% of our assignments are completed in an average of 20 days." Is this a meaningful claim? Or is it kind of like saying, "60% of the time, it ...
0
votes
1answer
16 views

How do i find weighted normal vector?

How do I find the weighted average of a normal vector. Heres a phrase from my book a weighted average might be used where the weights are determined by the areas of the polygons (e.g., polygons with ...
1
vote
3answers
130 views

Probability of two normal random variables when random samples are taken from a population

This is sort of second section to my previous question, I should have included both together, but I forgot to. Sorry for any inconvenience. X= random height of a male Y= random height of a female X ...
1
vote
2answers
132 views

Probability of a normal random variable added to a number being greater than another normal random variable, and distribution of average

$X$= random height of a male $Y$= random height of a female $X$ and $Y$ are independent of each other For $x$, $\mu=180\text{ cm}$ and $\sigma^2= 16\text{ cm}^2$ For $y$, $\mu=170\text{ cm}$ and ...
0
votes
0answers
31 views

Is this a proper formula for return rate?

Suppose we want to find the return rate of a casino game. For example, if a player brings 1000 USD to the game, pays a total cost of 1000 USD to play the game, regardless of the amount won (I will ...
1
vote
2answers
42 views

Calculate the average as numbers arrive

So, suppose you have to calculate the average of a set of numbers, but you don't know the whole set yet. Someone is providing you one number after the other and you cannot use more than the current ...
2
votes
0answers
25 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 ...
0
votes
1answer
16 views

As stock prices travel down what formula would you use to break out of a position

Suppose you are trading stock and you do not enforce a stop loss. Instead, you allow the stock to go where it wants. At some point, the value of your stock has dropped significantly and when the ...
2
votes
1answer
68 views

Average question GRE

The average daily temperature from 9th to 16th January(both inclusive) was 38.6 C and that from the 10th to 17th January(inclusive) was 39.2 C. what was the temperature on 17th January? I am able ...
1
vote
1answer
46 views

Meaningful statistic measure of data pairs

I have a dilemma. I have pairwise data, (a,b), that represents some form of speed, whether it's miles/hour or megabits/second. Let's say that we have the following set of data from measuring the ...
0
votes
1answer
43 views

Funny problem. How to average over periodic numbers

I'm want to calculate the average day and respective month that a specific event happens in a sample of countries. So for each country I have the date (one per year) of the particular event. Now my ...