# Questions tagged [statistics]

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27 views

### How much energy do all the world's emails use?

I have heard high level statistics and headlines around blockchain uses more energy than the Netherlands I am interested to compare this quantitatively to other utilities, for example email and ...
69 views

### Usage of the three-sigma limits in calculating minimum force

I have carried out 10 cantilever sample tests that provide a braking force as follows (in kN): 22.1, 20.98, 21.03, 20.7, 21.03, 21.09, 20.98, 21.08, 21.24, 21.19 The goal is to recommend the worst ...
43 views

### Covariance of an uncertain vector going through an uncertain rotation

I have a vector $\omega$ and it associated covariance, a rotation $\mathbf R$ and its associated covariance. What is the covariance of $\mathbf R \cdot \omega$ ? More rigorously: I have an estimation ...
32 views

### Choosing appropriate response type in experimental design (DOE)

I am designing an experiment to minimize the number of failures in wood-based materials arising from the application of wood screws. The first part is screening for significant factors and 2-way ...
47 views

### Compare Genetic Algorithms and Markov Chain Monte Carlo in their statistical properties in parameter estimation task

I am using GA and MCMC for estimating the parameters of a transfer function. GA returns results that each parameter has one value when minimizing the error function, and MCMC returns the whole chain ...
19 views

### When NOT to use Bessel's Correction for Standard Deviation

I can not find a clear explanation for when NOT to use Bessel's correction and use N instead of N-1. As I understand it, Bessel's correction would apply to things such as clinical trials, sampling ...
125 views

### Talking in terms of 6 sigma, why 4 ppm would be very costlier than 1 ppm (part per milion)?

In industrial manufacturing lines, there is a a limit on the number of discarded parts per million.I need to have a sense about this, e.g. How different is 4 ppm from 1 ppm and how much does it ...
64 views

### accurate measurements with less accurate tools

Is there a good way to systematically increase the accuracy and precision of a measuring tool using only mathematical means? For example, average 10 measurements from the same tool can create a ...
41 views

### Can you convert a histogram of linear separation of lines into a distribution (histogram, PDF, PMF) of their lengths?

I have an image of lines (they're actually crystal defects viewed through an SEM) What I'm really after is a histogram of line lengths, but as can be seen from the above micrograph, most lines exit ...
18 views

### How to sample Mean-Time-To Failure values from a Weibull Distribution with shape 1.5?

I have a mean time to failure (MTTF) recorded from 100 systems which is 6.5 years. The shape parameter of my component is given with k = 1.3 (based on a list the from literature). Now I want to ...
44 views

### How to find raw data sets for engineering?

For one of my courses the teachers asked me to find two samples of 30 or queries of data, and I was thinking on how I could begin to search it? Most of the scientific articles that i looked for ...
200 views

### Must MSA (Measurement System Analysis) be re-performed after annual instrument calibration?

I'm working in an automotive company that must follow IATF (International Automotive Task Force) requirements. I administrate a test-bench that performs RF (radio frequency) tests using an ...
86 views

### What measurement accuracy/precision is required to detect a 10% relative change in the measured quantity

I'm trying to design a measurement system, the primary objective of which is to reliably detect a 10% change in the the volume of fluid flowing through a pipe. I'm struggling to come up with a ...
21 views

### How can I calculate uncertainty based on measurements from multiple separate runs?

I am using standard test blocks to find the uncertainty of a supermicrometer, which is capable of measuring down to 1/10 of a micron. The issue is that it measures the EXACT same length within a run ...
1k views

### Double interpolation for a large set of data in Excel [closed]

How do you do double interpolation for a large set of data in Excel? The user is required to input an x value and y value then the program has to find the points and do interpolation if necessary. ...
224 views

### Find spring constant of frame structure

I would like to calculate the spring constant of a frame structure. I thought that I could do it like this: I apply a point force on the structure: Then I calculate the displacement at that same ...
83 views

### What is the best graph type to show a comparison value between two cases?

In that graph, I want to show the two values and the error percentage from the comparison between two values. I am using microsoft excel. can anyone give me any idea which best graph for this case? ...
28 views

### How to find all the parameters in weight vector in Levenberg-Marquardt Algorithm?

I already had a data for corroded thickness distribution (in matrix form) for corroded surface model in Abaqus with mesh size 5 cm I want to create thickness distribution with bigger mesh size (e.g 50 ...
79 views

### What does (a) the input of the activation function mean?

I am not very good at understanding the ANN theory, but please if anyone can explain me about what does (a) as input of the activation function mean? and how to get this value? Thank you
67 views

### How do I include statistical significant index in bar chart in excel?

I want to have a star dot above each bar chart. I don't know how to present that index. Please anyone help me to resolve this problem,
114 views

### DOE to optimize a chemical reaction with impurity forming in series

This question contains chemistry, but the main focus is DOE design--hence posting on the engineering stack exchange. The problem is a chemical reaction: A + B -> Product Product + B -> Impurity The ...
315 views

### Moments of inertia, rods mechanism

I need some assistance understanding moments of inertia. I am doing some review for an upcoming exam, however I am slightly stumped by this question. I have already tried googling "moments of inertia" ...
253 views

### Why Taylor's microscale gives us information about the smallest scales of the flow?

So I understand the principles of two-point time correlations (covariance) and how you can just normalise that to get the autocorrelation. I also understand the integral time scale which is quite ...
75 views

### Choosing significant figures when dealing with a wide range of values

In a calculation I have received a number of values in the range $1e4-1e6$. Now I would like to display the values with 3 significant figures according to the rules of using significant figures. But ...
69 views

### How do I update an individual control chart?

I'm finding myself using control charts and I'm unclear on a very basic point. I've read page after page of texts, but they all focus on how to make the initial chart rather than walking you through ...