Questions on the use of mathematical techniques to extract properties from given data. Consider if your question might be more suited for Cross Validated (stats.SE) instead.
Questions tagged [data-analysis]
1056 questions
1
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1 answer
Detecting periodic patterns in data - how often are the meetings held?
Suppose some people I know frequently have meetings, and suppose I want to find out whether there's a pattern to when these meetings take place, and if so how often they occur.
I can take note of the days when they have meetings. If I assume that…
Sp3000
- 1,562
0
votes
1 answer
Chart Question and Percentages
The Venn Diagram above represents the 20 students who took one or more of the 3 available art class or took no art class at all. What percent of the students took only 1 art class?
A. 10%
B. 20%
C. 30%
D. 40%
E. 50%
user159778
0
votes
3 answers
fit sine wave to data
I have some astronomical data that I want to fit a sine wave to.
I want to fit something of the form
y = Asin(Ωt+Φ). I know the period of the sinusoid is equal to a sidereal day. So I know the frequency Ω. So, I just need a way to find out optimal…
Vivek V K
- 161
0
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1 answer
matching two curves
I have two curves extracted from some data and I'm trying to detect when there is a difference. Each of these 3 plots represents a different data set.
From these example curves below, I'm looking for a metric that I can use to compare the green and…
YMDW
- 116
0
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0 answers
Two Part Question Regarding Function Analysis and Encryption
I've been to my professors office hours, and my teaching assistants are not making this clear for me. Encryption is such a great field of study and I really would like to get off on the right foot. Any input would be greatly appreciated.
Two part…
BajaBob
- 123
0
votes
2 answers
Function to fit a curve
I am trying to fit a function to data that looks like the following.
I have no idea what the function is, but by visual inspection it seems to be a parabola (or some other convex polynomial) + a scaled sinusoidal whose amplitude increases more than…
nvk
- 113
0
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0 answers
Handling "<5" Values in a Count Column for Case Rate Computation
I am preparing data for spatial correlation analysis. In one column I have integer values '<5' and values ranging from 5 to 2321.
The values represent counts of cases that I intend to use with the population column to get a case rate. What is the…
J. sva
- 43
0
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0 answers
Compare and Represent Data With Different Number of Elements
I have N entities that I want to compare them to; for example, A has 5 options, B has 3 options, and C has 6 options. 1 means an option exists, 0 otherwise as in the example next:
A = [1 1 0 1 1] (satisfied by 4 options out of 5)
B = [1 0 0]…
mmain
- 101
0
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1 answer
Need method to fit specific function to measured data
I have a function
$$ f(x, a, b, c, d)=\frac{a+b \times x}{c+d \times x}$$
where for a set of different x there are measurement results corresponding to $f(x, a, b, c, d)$. It is the parameters $a, b, c,$ and $d$ I would like to fit.
There seem to be…
0
votes
1 answer
SAT question - plotting and linear model
I am tutoring someone in preparation for the SAT. Below are two SAT questions that I find bothersome. I have the answers but disagree with the official answers and would appreciate understanding the SAT train of thought if anyone can conjure it…
Better2BLucky
- 305
0
votes
1 answer
Calculation of the error for the weighted arithmetic mean
I am trying to derive the error for the weighted arithmetic mean
$$
\langle A \rangle=\frac{\sum_{i=1}^N \frac{A_i}{\sigma_{A_i}^2}}{\sum_{i=1}^N \frac{1}{\sigma_{A_i}^2}}.
$$
of a Data-Set $A_i$ with the errors $\sigma_{A_i}$.
With the gaußian…
Roger
- 165
0
votes
3 answers
Curve fitting with an invertible function
I have some data that need to be transformed as shown in the picture given some function.
example of input data and desired result
The function in question can take whatever form but with the following requirements:
It needs to be able to fit the…
0
votes
0 answers
Normalizing data between 0 and 1
I've got some data that I need to be normalized. I've tried several different ways I've found online, none of them work the way I'd like. I've tried (x - mean) / standard_deviation, where x is my value. I've also tried (x - min) / (min - max) as…
sivSivSG
- 1
0
votes
1 answer
Upper values of a data set
I have a data set composed of 840 samples. Each sample is contained in the range [0, 100]. Plotting them as a scatter chart it looks like this:
As can be seen in the chart, there are some points which are distributed in the top part (around 80 on…
Boni García
- 103
- 4
0
votes
1 answer
Rate of Growth of pyramid structure.
This might be simpler than I'm making it out to be, but how can the growth rate of the pyramid structure be represented.
1
/ \
2 3
/ \ / \
4 5 6
/ \ / \ / \
7 8 9 10
Firstly I thought its n+1 but that is only…
user2059239
- 11