Mathematics Stack Exchange
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Questions tagged [average]

Averages summarise a set of values in one way or another. Without further qualification it most commonly refers to the arithmetic mean, but other averages such as root-mean-square exist.

In its most general definition, an average is a summary of a set of values. Normally it refers to the arithmetic mean, but other means may be employed (geometric, harmonic, etc.) or a transformation may be applied before and after taking a mean (e.g. root-mean-square).

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Calculate new average from two other averages with its respective totals/counts

I have the next film named Blade Runner and it has two version (director cut and theatrical cut) and I rate the director cut with a 7 and the theatrical cut with a 8, so the average would be: (7 + 8) / 2 = 7.5 I have another average of all films…
dashaus
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Calculate average lifespan

We want to calculate the average lifetime of our customers. For each customer we know when they joined, whether they are still with us and if not, what date they left us. Our company has exponential growth, so most months we acquire more customers…
migu
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Simultaneous Equations.

Erin goes off on a long bike ride at 10km/h. One hour later her brother starts chasing after her at 16km/h. How long will it take Alistair to catch up to Erin? Solve with simultaneous equations.
MiketheKnight
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Number of Likes and Dislikes to Star Rating system

I have a 5 star rating system that outputs a recommendation. A user inputs a rating based on a Like or Dislike. What I would like to know is how to convert the number of likes and dislikes into a number which can be put into a 5 star rating…
user3180997
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Calculating Average Percent

I have two ways to calculate the average starting price of an auction item compared to it's actual value. Starting Value Actual Value Percent -------------- ------------ ------- 1 2 50% 2 3 …
yurisich
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Specific average calculation

Suppose I have a set of weighted grades for a subject in high school. Like this: 8.4 (weight: 3), 7.2 (weight: 1), 3.4 (weight: 3). When I loop over that set like this: totalCount: Double totalWeight: Integer for grade in grades { totalCount +=…
Johann Behrens
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Problem finding the median when using frequency tables

My question concerns finding the median from a frequency table. It only occurs if you have even amounts of data. My problem is this if I had 40 bits of data in a grouped frequency table the middle values would be the 20th and 21st data points. That…
Ben Parratt
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Is This a Weighted Average

I would like to know whether a weighted average can be defined as the product of the different values, to the power of their weights? Basically, I have this formula and I have to describe it in one or two…
Docksan
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Shop keeper mixes 3 varieties of wheat?

A shop keeper mixes 3 varieties of wheat costing ₹12, ₹14 and ₹17 per kg. Which of following represent ratio of mixing of varieties if the mixture is sold at ₹15 per kg and he gains 20% profit ? $ (1) 23:7:2 \quad (2)27:6:1 \quad (3)25:6:4…
prashant singh
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SAT Math Question Confusion

I was doing a practice new SAT Test and was wondering exactly what this question is asking and how it got to the answer. Thanks!
rassa45
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Five-year Annual Average vs five-year Weighted average maintenance costs for two car types

If we are comparing maintenance costs (M$) per mile (M$/m = Mtype) of two car models over a 5 year period, where the number of cars that are type (a) is much less than type (b), and the number of type (b) cars keeps increasing at a faster rate than…
Wayne
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compute a value based on goegraphic range from measuement devices

Today is one of those days when the correct method to calculate this escapes me. I have 3 fixed points on a map where measurement devices are located. These all track the same transmitters. A mobile unit operates somewhere between the measurement…
J Hinton
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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 = $\frac{f(x+h)-f(x)}{h}$ $$=\frac{x^2+2xh+h^2+3-(x^2+3)}{h}$$ $$=\frac{h^2+2xh}{h}$$ $$ = 2x+h$$ What must I put in place of x?…
Aspiring Mathlete
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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 (a,b,c,d,f) and so on. Is it possible to solve for…
Mantracker
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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 ?
deldev
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