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
5
votes
4 answers
fit sine wave to data
I have some astronomical data which I know has a sinusoidal component to it of the form
y = Asin(Ωt+Φ). 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 values for A and…
Vivek V K
- 161
5
votes
2 answers
Way to compare three numbers with an algorithm.
Say I have values
10,
3,
6
What would be a way of finding a subjective difference between them. Or in other words, how close they are to each-other.
So if i had
3, 2.5, 2.8; they would be close together in relation to one another.
3, 10, 10.5;…
Jamie W
- 57
4
votes
3 answers
Kalman filter with sensors having different sampling rate
I would like to implement Kalman filter scheme with two different kind of sensors - say 9DOF IMU (gyro/accelerometer/magnetometer) and GPS sensor (position/velocity/altitude).
Problem is, as i understand, classic Kalman and Extended Kalman filter…
4
votes
1 answer
Logistic functions - how to find the growth rate
We have the formule for a model with logistic growth:
$$ N_t = N_{t-1} + g\, N_{t-1}\left( 1 -\dfrac{N_{t-1}}{K}\right)$$
where $g$ defines the growth rate and $K$ is the carrying capacity.
Let's say we have the following data:
$N_0 = 10$,
$N_1 =…
4
votes
3 answers
pdf of sum of two dependent random variables
What is the pdf of sum of two dependent random variables given we know their joint
pdf and individual pdfs. I have seen already some posts but none of them answered when they are dependent. Every one solved for only the independent case but i need…
user263042
- 37
2
votes
1 answer
Data Analysis and Probability
Two dice with a difference ... They appear identical, but one die is fair and the other is loaded so that the probability of throwing a 6 is 0.25.
Bev picks a die at random and throws it, and it shows a 6. Find the probability that she picked the…
dataquest
- 23
2
votes
0 answers
curve fit but unknown function
I face a strange problem.
I have data $[X,Y]$ with no noise. If I plot $Y$ as a function of $X$, it looks like a straight line and the regression coefficient is quite good.
For the simplest model $$Y = 1 + aX\\
a = 0.328841508328634 ±…
Claude Leibovici
- 260,315
2
votes
0 answers
Summing specific levels of a factor variable in R
I have two factor variables, one for smoking and one for sport -
Smoking status: 1 (not), 2 (occasional) and 3 (regular, i.e. more than once per week)
Sport participation: 1 (not regular) and 2 (regular).
smoking_status <- data_1995$smoke
smoke <-…
James
- 21
2
votes
1 answer
Computing a single value within 0 and 1 from a set of features
I have a set instances with features that I would like to compare with a reference set of values. For example, I have the instances with their features below:
\begin{array}{|l|l|l|l|}\hline
Arrival Time & Departure Time & Processing Time & Wait Time…
kbb
- 123
- 2
2
votes
1 answer
Compare Two Values - Stardew Valley Food
In the game, Stardew Valley, you can pick up items through farming, fishing, foraging, cooking, etc. Most tasks use up your character's energy, such as swinging an axe or using using a watering can. Most items in the game can be sold to get gold or…
Swiftmatt
- 21
2
votes
1 answer
Solving equations with 6 different gaussian function
I have a large dataset coming from absorption spectroscopy experiment and i'm facing a problem to extract relevant informations. My matrix look like this :
$ S_n(x) = \left( \frac{a_n}{\sigma_1\sqrt{2\pi}} e^{\frac{-(x-\mu_1)^2}{2\sigma_1^2}}…
Julien
- 21
2
votes
1 answer
How to turn data into functions
I'm reading this over at the Khan Academy and they use the function $f(n) = 6n^2 + 100n + 300$ in their opening discussion of asymptotic boundaries of algorithms. My question is not specific to this example, but general, that is, how are such…
147pm
- 920
2
votes
2 answers
Scaling range of $n$ numbers to $m$ numbers
I have $n$ values ($n \approx 10^8$) ... I want to plot these, where the $i$-th value is plotted at point $(x,y)$, $x=i$ and $y=$value$[i]$.
Note: The values do NOT follow any pattern or function. They are RANDOM values - that represent load on a…
Boopathi Rajaa
- 123
1
vote
1 answer
Waveform filter - what's in the black box?
I'm trying to come up with an algorithm or filter that has the i/o characteristics in the image below (waveform plotted from audio data) .. I input a sine wave or saw and the resulting graphic is an area filled wave.
I've been trying different…
Rob
- 13
1
vote
2 answers
How to interpret the result of correlation between two discrete signals
Before starting, let me say I'm not a mathematician, I'm just a curious engineer, with a master's degree in engineering and computer science.
I have been using this book The Scientist and Engineer's Guide to Digital Signal Processing for years, as I…
carlosrafaelgn
- 115