Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [statistics]

45 questions
17
votes
3 answers

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 should a measurement of $9.1$mm be treated? Clearly…
nivag
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1 answer

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? Reference: Pareto analysis
Mahendra Gunawardena
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10
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3 answers

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
JHK
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8
votes
3 answers

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 replaced. The majority of these units have never…
Stephen Collings
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7
votes
5 answers

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 specification, and they purchase these parts for the plant to…
user1586
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6
votes
3 answers

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 power supply samples. The samples have been tested…
Mahendra Gunawardena
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5
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1 answer

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 measuring is. One can also calculate "uncertainty"…
Nova
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5
votes
4 answers

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 could be a bottleneck and the other week not. I…
user78820
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4
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1 answer

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 failure percentage. We are developing a pro active…
Jonab Kornell
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4
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1 answer

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 available. I have a single output variable calculated…
Carlton
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3
votes
3 answers

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 part of the end product. As result of sharing…
user1586
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3
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0 answers

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} - \mathbf{f}(s_0)) + s_0$ where $\mathbf{w}$ is a…
user135172
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3
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Relationship and interpretation of "discrete" and "continuous" covariance matrices in Kalman Filtering

I am quite confused about the interpretations/implementation of the system and measurement noise covariance matrices for the continuous and discrete time Kalman Filter. What I want is to initialize those matrices with physically meaningful values…
link
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3
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1 answer

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 (or isn't). Recreational lifters, other types of…
user16
3
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1 answer

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,
Cindy.Karina9
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