# Questions tagged [data-analysis]

Use for question relating the the techniques of data analysis.

337 questions
Filter by
Sorted by
Tagged with
1answer
24 views

### How to find the period of a pendulum knowing only its speed and maximum arc-length?

I am writing a program to give me the period of a pendulum, the program can measure the speed of the pendulum at every 1/60th of a second (Limited by camera frame-rate.) Is it possible to know the ...
0answers
55 views

### Discovery of a new particle [closed]

Why do we only confirm the discovery of new particle when standard deviation is approx $5\sigma$. What is the probability associated with $5\sigma$ standard deviation. Be little rigorous.
2answers
36 views

### Simplifying acoustic test procedure — don't want to bother neighbors with party!

I am having a party and would like to keep disturbing neighbors to a minimum, but maximize the volume we can get away with. I devised a quick n' dirty test plan to generate some frequency response ...
1answer
32 views

### Determine speed of moving vehicle from video taken in a moving vehicle [closed]

I have dash camera footage from my motorcycle where the police were speeding illegally in dangerous conditions. I know my speedo is 7% over so if it reads 107KPH a radar gun will ping me at 100KPH. I ...
0answers
37 views

### How to find the integrated luminosity for a 5$\sigma$ discovery?

I was thinking about the procedure needed for the discovery of a new particle. Suppose a data-analysis aims at searching for a new resonance X decaying to two electrons after collecting 20 fb$^{-1}$ ...
3answers
63 views

### Should we include instrumental uncertainty when calculating the uncertainty of a measurement?

Imagine we are measuring the period $T$ of a pendulum using a stopwatch The stopwatch has an inerent instrumental uncertainty (e.g. 0.1s) let's keep this fact in mind Due to random error (let's ...
1answer
36 views

### Uncertainty in data from star databases

I have students who are pulling data from various astronomical databases like SIMBAD or the Binary Star Database and then using that data to determine correlations between certain properties. My ...
4answers
982 views

### Help interpreting “five sigma” standard?

So, I am coming from a math/stats background. I was just wondering about this in the abstract, and tried Googling around, and came across this article which says the following regarding some ...
1answer
19 views

### Polynomial regression and errors weighted with square root of reduced chi square

I conducted a polynomial regression of the form $y(x) = A+Bx + Bx^2$, and would like to obtain parameters $A$, $B$ and $C$ and their respective errors/confidence level. The reduced chi square is less ...
1answer
21 views

### How to extract velocity and acceleration from $N$-body simulation data?

I have data from an $N$-body simulation and want to do some data analysis. I would like to extract the velocity and acceleration of each particle. The data consists only of the positions of each ...
4answers
100 views

### Is the Least Squares Fit always the accepted Fit in Physics?

Is the Least Squares Fit always the accepted Fit in an experiment? Suppose you have $N$ data points and a function $f$ with some parameters. There is a one Least Square sum, it may be obtained for ...
0answers
24 views

### Intuition re. log scale versus linear scale

I have a dataset with the speed of movement of two sets of particles (the red, slower, and the blue, faster) as calculated by the diffusion constant. Below is a histogram, on the left on linear scale ...
3answers
21 views

### How to display an measurement results with error bar given huge number of digital measurements? [closed]

I need to measure the flow rate using a flow meter. This flow meter collects 6000 data points over the course of 5 minutes for every temperature of our experiments. I repeat this experiment at ...
0answers
25 views

### $S$-Parameter Phase in Matlab

I'm trying to plot the phase of S-parameters on Matlab. The data I have is the coupling matrix (M) of the system and from that I have extracted S11 and S21 (column 1 in image is frequency and column 2 ...
1answer
47 views

0answers
7 views

### Mean of gradients or gradient of mean points

I have 5 repeat measurements of a dependent variable for each of 5 values of an independent variable. To find the gradient and estimate its error, is it better to plot the 5 mean points and find the ...
2answers
55 views

### What do I set for the standard deviation of a measurement, if the value is not normally distributed?

I took multiple $B$ measurements for a constant $A$ value, which I simultaneously measured. $A$ (in my case the resistance of a temperature sensor) was controlled by a PID controlled and slowly ...
0answers
29 views

### FFT on a signal with a length that is not a multiple of the period of its harmonics

I was very surprised to find an apparent limitation to a FFT on a simple signal. Let's consider a timeseries made of L=100 points, and simply composed of the sum of two sinus waves: one with a ...
1answer
19 views

### How can I cluster infrared spectra?

This is sorta a cross-post from my post in StackOverflow. Although, rather than seeking help with the code I'm here asking for help with a physical/mathematical/statistical problem associated with the ...
2answers
32 views

### What is the difference between horizontal units and horizontal scale at an oscilloscope?

This is a picture of the data of a given measurement by an oscilloscope. I would like to know what the difference between horizontal units and horizontal scale at an oscilloscope is. I would be so so ...
1answer
214 views

### Why do I have to draw a big triangle to determine the gradient of a straight line using the slope triangle method?

I'm an igsce student, I'm taking igsce OL phyiscs. It's stated in my book that after I draw a graph and the line of best fit, I should get the gradient by choosing two points then form a right angel ...
0answers
26 views

### Magnetic flux as a function of distance experiment

For my electrical engineering senior design I created an experiment to test magnetic flux (more voltage) increase from a material in a coil of wire. There is a large sending coil with A.C. voltage and ...