# Questions tagged [engineering-statistics]

Engineering statistics combines engineering and statistics using scientific methods for analyzing data. Engineering statistics involves data concerning manufacturing processes such as: component dimensions, tolerances, type of material, and fabrication process control.

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### Confused when to use Population vs Sample standard deviation in engineering testing

When I run an test for something (say 10 trials) and want to find the standard deviation of all 10 trials, I am getting confused if I should use the sample or population standard deviation. My initial ...
31 views

### Comparing three measuring devices, should I analyze the measurements or the resulting regressions?

Background: The operator has three measuring devices D1, D2, and D3. The devices are all the same make and model. The devices can rapidly measure material property X. The operator really needs to know ...
17 views

### Statistical design for failure analysis

I am designing a test plan to find factors that correlate with pavement failure. Failure is a rare occurrence. How would I go about designing the test? I have N factors, with various factor levels, ...
48 views

### Predicting failures of a part using historical failure data

Suppose I want to forecast the number of failures of part $A$ operating in my system. In my repertoire, I have historical failure numbers for part $A$ as well as the number of units of part $A$ that ...
185 views

### When to use hypergeometric vs binomial

I'm having some trouble understanding if I need to use a hypergeometric distribution. I have a set of components, a small proportion of which are faulty. I now want to know if a feature of that ...
15 views

### Estimating failure rate in a changing population of identical widgets

We wish to estimate the failure rate of a changing population of indistinguishable widgets. Starting with zero widgets, at the start of week $w$ we observe the number of new widgets $n_w$ added to ...
107 views

### How do I calculate the probability that some system will survive for some years before some event will occur?

I have a failure rate problem involving structural beams. The scenario is that a set of $n$ structural beams are supporting a weight of $W$ kilograms. For the purpose of simplification, we can assume ...
62 views

### Possibility n independent random events ocuuring per year? An event is any piece of equipment failing per year

So I am an engineer. We have a method at our organization of defining the probability of an equipment failure based on frequency of occurrence. So for example we may categorize a piece of equipment ...
337 views

### How To Calculate and Print CDF and Lower Bound CDF value for some t (time) with Minitab (without examining the plot)

I'm a reliability engineer. Cumulative Distribution Function (CDF) in statistics stands for the unreliability (probability of failure at a time value) of the item being tested. Unreliability is very ...
107 views

### What constitutes a significant drop in speed of vehicles on a 40mph road?

A friend had an incident near where he lives recently that is similar to my line of work (currently) that made me think what constitutes a significant drop in speed as a result of a change in road ...
33 views

### Usefulness of decomposition of time series in a panel data regression analysis setting?

So, I am working with panel data. The different panels are for the different inverters that are present inside a solar plant. Each panel has variables that are time variant and are sampled at a 15 min ...
31 views

### Opposite sign for a parameter estimate in cox regression (freeze and thaw effect on reinforced concrete bridge deck surfaces)

I would like to model the freeze and thaw effect on reinforced concrete bridge deck surfaces using Cox Regression. But the parameter estimate is negative which is the opposite of the reality. When the ...
110 views

### Dimensionality reduction of highly correlated features for predictive maintenance

I have a high dimensional sensor data and many variables are highly correlated. Is it a good idea to get principal components without removing correlated features to reduce dimensions? My final ...
920 views

### Predictive maintenace model to identify indication of failure before it happens

Situation I'm working on a problem where I'm using sensor data to predict machine failure before the failure happens and I need some advice on which methods to explore. Specifically, I want to ...
49 views

### Sample an Interval on Continuous Variables, Intervals, Statistical Significance, Sampling - Applied Stats Question

Let's say I have a segment of pipe of length $X$ that I want to test the integrity of by way of a hydrostatic pressure test. That is, I isolate the ends of the pipe and pump water into it until it a ...
1k views

### Book recommendations for reviewing probability and statistics for engineering major

I'm an Industrial Engineering Major and I'm looking out for book(s) on Probability and Statistics (Combined would be preferred but separate would do as well) which : I, as a self learner, can work ...
29 views

### How to deal with overlay censored reliability or survival analysis (over 95% of the data would be censored)?

I have data for Engineering structures that are built sometime after 1900 until recent years. The inspection data for these structures are available from the 1980s onward until now. The inspection ...
706 views

### Does every statistic have a sampling distribution, not just the sample mean?

I am curious because most basic undergraduate statistics reference just start out Inferential Statistics by mentioning sampling distributions and the sampling distribution of the mean. My question is ...
14 views

### In my study of Inferential Statistics, the following uses of inferences were mentioned. Could this be expanded upon?

Currently an undergraduate engineering student studying Statistics. My source has cited three major uses of inferences: Types of Inferences Estimation - The value of a parameter is estimated. Testing ...
51 views

### What to do if the range of an input factor changes after running the experiment?

I am gaining my first experiences in Designing Experiments and here where I am stack: An experiment has been run with some continuous input factors: x1, x2, ..., x5. The goal of the experiment was to ...
46 views

### Predictive maintenance machine learning model to identify a failure before it happens

I have 1000 industrial sensors that send data once a day. The 10 sent parameters along with sensor pass/fail info is stored. The data format is below. If a sensor fails there is no further ...
33 views

### Calculating the probability distribution for Hardware defects based on history of defects

I'm writing a study about Hardware status in my institution. I've gathered data about hardware failures over time (I know how many failures happened each semester each year on a specific hardware ...
26 views

### modeling a electrical pulse which is technically time dependent

I have an electrical pulse that I need to fit a curve to a certain area of but not the entire thing. The whole pulse looks like this However the only part that I need to model is this My boss ...
50 views

### What is the best syllabus for an under-grad class in Statistics for engineer students?

I teach statistics to under-grad engineer students who major in Information Technology (IT). My students first learn a (prerequisite) course on probability where they learn combinatorics, different ...
64 views

### Useful data analysis methods for engineering applications [closed]

I'm currently working on a dynamic simulation of an already existing product. The simulation is supposed to help in future development of this product by enabling the engineers to get a better ...
30 views

### What is the name of this kind of statistics problem and where can I go to learn how to solve it?

I have a heuristic model of a physical process which is dependent on outcomes from random variables. The physical process approximated by the random number generator suggests what the distribution ...
1k views

### Reorder point with stochastic lead time and demand

I'm trying to determine the optimal reorder point for some products. The reorder point must be greater than the demand during lead time a $\%$ of the times that I should determine, let's say $95\%$. ...
109 views

### If the population size was large enough that the sample size required to represent it is too large to be practical, what should be done?

i just started working as a quality control engineer at a poultry company, one of my first duties is to design a mechanism to ensure the quality of the end product (the Chick) and processes leading up ...
406 views

### Clustering issues

I have a list of electrical feeders. I want to cluster them by their topological characteristics: voltage level, total length, % of underground cable, state of the neutral. I first made a manual ...
88 views

### Grad level books for survivability analysis applied to manufacturing

I am looking for a grad level book on survivability analysis applied to manufacturing such as assembly lines. Preferably in R. I am familiar with measure theory, probability theory and R.
36 views

### How to stabilize features over time?

I have in my model some features, which seem to have some super power to explain the training data. To be more specific, the model is to predict clicks and the features are the click-through-rate(CTR)...
I am given 15 points. The control limits are at +/- 3 $\sigma$. Points 1, 4, 5, 6, 7, 8, 9, 10, 11, 13, and 15 fall within the control limits. Points 2, 3, 12, and 14 are outside of the control limits,...