The sum of several numbers divided by their count nicely summarizes the overall size of the numbers involved in a single value.
0
votes
2answers
59 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 ...
0
votes
1answer
69 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
58 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
1answer
125 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 ...
0
votes
1answer
59 views
Algorithm to Get a Product score based on rating
I am trying to device a algo for product score. Here are the inputs
User rates a product on 5 different criteria out of 10
Each criteria has a different weightage with all adding up to 100%
There ...
0
votes
0answers
24 views
How do I smoothen / average the withdrawal percent?
I need help with finding an appropriate formula to use in this scenario. I am trying to solve the famous 4 percent withdrawal problem. Here's the problem statement:
On a form, user enters his ...
0
votes
1answer
36 views
Which of the following cannot possibly be the average - Standardized Test
I came across a question while preparing for a standardized test that is kind of confusing. Hope you guys could help me out here.
The question is:
Three men have weights that range from 110 to 135 ...
0
votes
1answer
218 views
Error propagation and averages, a practical question
Ok, I'm sure this is simple, yet I'm confused.
Lets say my goal is to obtain an average concentration C=N/V so I take a number of N and V readings with errors:
$N_1=50\pm2, V_1=100\pm4$
...
0
votes
0answers
46 views
Calculating score
I have a number of values, grouped by some category. For every category, I've calculated average and standard deviation. Now I want to calculate a score (say 1 to 1000) for every category.
I don't ...
0
votes
0answers
69 views
Weighted averages for recommendation engine
I need help on how to perform this calculation.
I have a list of songs. I know the band members, the genre (ex hard rock) and the parent genre (ex rock), and the time of the last update/activity ...
0
votes
2answers
94 views
How to compute 2 grades, one statistical (IRT) and other normal, together, to make a fair average? [closed]
An exam is composed of 2 tests. The first test's grade is fixed at 500 plus or minus 100 for each standard deviation obtained, calculated by computer using the Item Response Theory. The second test ...
0
votes
1answer
527 views
Charting Histogram Averages and Standard Deviation
Pretty basic question I'm sure:
I have a 100 histograms, they are all created from randomly sampling the same data 100 times.
Now, I want to show the 'average histogram' with markers at +1 standard ...
-1
votes
1answer
345 views
Calculating a 5 star rating with a reputation number… [duplicate]
Possible Duplicate:
5 star ratings. Bayesian or Weighted average?
Similar question, but unlike that question this deals with two factors the stars and reputation.
Lets say Stack Exchange ...
-1
votes
1answer
693 views
Normalizing a matrix using matrix operations
I need some help in normalizing my matrix. I have a 5X4 matrix A. I want to normalize each column. Following is the explanation on the operations
B = Operation of matrix (A)
B matrix is 5x4 matrix. ...
-1
votes
1answer
134 views
Applying fuzzy logic to determine the degree to which a project is complete
I have a Project made up of tasks.
Each task has an estimated completion percentage.
I realise I could treat each tasks completion percentage as a representation of the degree of membership to the ...
-1
votes
1answer
898 views
Can weighted average be used to calculate percentage increase? [duplicate]
Possible Duplicate:
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:
...
-2
votes
2answers
389 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.
-3
votes
1answer
41 views
Quiz averages, statistically fair? [closed]
I was wondering if it is statistically fair to take the percentage of three separate quizzes that are not worth the same amount of points and divide it by 3 to take an average grade. For example, quiz ...
-4
votes
1answer
60 views
Doubts about Average, Proportion & Ratio
Question 1 : In a team of $11$ players the age of the captain is $26$ and that of the wicket keeper is $3$ years more than the captain. If the average of the ages excluding the captain age and the ...
