We’re rewarding the question askers & reputations are being recalculated! Read more.

Questions tagged [statistics]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
-5
votes
2answers
102 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 ...
0
votes
4answers
52 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 ...
0
votes
0answers
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 ...
1
vote
0answers
13 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 ...
0
votes
2answers
42 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 ...
-1
votes
1answer
100 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 ...
1
vote
1answer
52 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 ...
1
vote
0answers
18 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 ...
1
vote
2answers
463 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. ...
1
vote
1answer
150 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 ...
1
vote
1answer
51 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? ...
1
vote
0answers
20 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 ...
1
vote
1answer
68 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
3
votes
1answer
44 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,
3
votes
2answers
99 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 ...
1
vote
2answers
177 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" ...
2
votes
0answers
232 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 ...
1
vote
2answers
71 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 ...
2
votes
1answer
62 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 ...
3
votes
3answers
77 views

Guidelines to develop quality engineering training content and select a trainer

Our organization has recognized the need to improve quality of both incoming material and outgoing products. Our products are primarily electrical/electronic but mechanical components are an integral ...
3
votes
0answers
24 views

Pearson correlation of neural responses with it's linear estimation

I am trying to anderstand the following fact from this article (page 13): How can single neurons predict behavior Suppose I have a linear estimation of a stimulus: $ \hat{s} = \mathbf{w}^T(\mathbf{r} ...
10
votes
3answers
8k views

How do you determine the accuracy of a measurement device?

Lets say you have a measurement device of which you do not know the accuracy, and a reference measurement device. Both measure a variable $x$. The range of interest is $x_0<x < x_1$. How do you ...
4
votes
1answer
141 views

Statistical approach to defect detection and prioritization

My company has over 100k communication devices deployed. We collect failure information from the devices. We have two type of data failure count per hour for each device and we use that to calculate ...
8
votes
3answers
1k views

How do I properly compute mean time to failure?

I have a product of which we have shipped something like 500 units over the last five years. This product is not intended to be user serviceable; a failure of any component results in the unit being ...
4
votes
1answer
77 views

How to display data with three degrees of freedom on a chart?

I have a collection of data obtained from calculations and I want to display it on a chart or whiz-wheel or similar, to be used "in the field" as a low-tech solution, since no computer will be ...
7
votes
5answers
1k views

How to identify low quality electronic components early?

Our component sourcing organization purchases large amount of electronic components from suppliers. I believe this is through a bid process. Engineering provides the sourcing organization ...
5
votes
4answers
355 views

How to compare utilization rates?

I have the utilization rates of several machines for each week over a year. These differ per week because of the occurrence of machine failures and changes of orders. Meaning that one week a machine ...
2
votes
1answer
921 views

How to determine if an engineering process is stable and capable?

Mostly interested in understanding how engineers determine if an engineering process is stable and capable, particular in design for manufacturing (DFM) frame work for components. Some example ...
5
votes
1answer
134 views

Question about “uncertainty”

I'm a bit confused about all the different "definitions" of uncertainty? One can calculate "uncertainty" of a single measurement by simply checking how accurate the tool that is being used to do the ...
6
votes
3answers
244 views

How can the vendor be approved/disapproved based on validation test data?

The power requirement for a sub system is 5V +/- 10% @ 1A of current. A RFQ was issued and a prospect vendor was selected. A first article of inspection (FAIR) has been submitted which includes 15 ...
10
votes
1answer
724 views

How can Pareto Analysis help solve engineering problems?

Attach is a Pareto Diagram with Number of Defects in Y-axis vs Causes in X-axis for an engine overheating problem. How can this Pareto diagram help an engineer solve the engine overheating problem? ...
2
votes
1answer
88 views

Estimating maximum lift or strength

Weight lifters will use the term "one rep maximum" in order to refer to the maximum amount of weight that they can lift one time. The one rep max is often used as a proxy for how strong someone is (...
15
votes
3answers
3k views

How does measurement uncertainty combine with tolerances?

Given a tolerance within which your workpiece should be manufactured, say some length should be $10\pm1$mm. If you determine that your uncertainty in measuring this length is $0.2$mm (at 95%). How ...