# Questions tagged [application]

applications of statistics and statistical modeling

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### How do companies decide the warranty period for a product?

$\text{Question:}$ A firm produces machines with a lifespan, whose distribution has a mean of $\mu$ months and standard deviation of $\sigma$ months. The firm wishes to introduce a warranty scheme in ...
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101 views

### Is it possible that one estimator performs better than others when sample size $n$ is small but performs worse than others when $n$ is large?

Are there any examples that one estimator performs better than others when sample size $n$ is small but performs worse than others when $n$ is large?
• 305
1 vote
118 views

### Why is CIHI recommending that we multiply the multiplicative error estimate by the per-capita rate?

I feel like this question is mostly about how to translate vague documentation into math than a statistics question per se, but please bear with me. I am reading the Canadian Institute for Health ...
• 9,381
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### Would the distribution of the average number of correct answers for a five-question game constitute an application of the central limit theorem?

Say you have a game in which users answer five questions daily. Would the distribution of average scores for a single user among all of their games meet the criterium for the central limit theorem? I ...
27 views

### Practically and probabilistically modeling discrete data that can take on a countable (potentially infinite) number of values?

As an example, let's say that we have observations of the price of some good at various points in time and would like to predict the distribution of the price of the good one point in the future from ...
• 451
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### Can using the IQR/Median help with this problem?

I have a set of data in tabular form which records the time it takes 500 people to bake a cake. Each person is assigned a single time: it may take Tom 30 minutes, or Mike 60 minutes to bake a cake. ...
2k views

### Methodology for Reconciling "all models are wrong ..." with Pursuit of a "Truer" Model?

When attempting to model various phenomena, in practice, our model will usually be "wrong", but can still provide us with useful insights/predictions. What methodologies can we follow to ...
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1 vote
38 views

### Names of actual software which use the LDA classifier

I read generic claims online and in papers that the Linear Discriminant Analysis (LDA) classifier is widely used for many applications including: face recognition, speech recognition, medical ...
36 views

### Trying to find the appropriate statistical method(s) to answer a marketing question — analyzing composition of groups

I’ve got roughly 90k rows of data, where each one represents a customer at my company. One of the columns tells me the channel that brought that customer to my company. I’m looking at the channel mix ...
77 views

### Quote on too good to be true model performance

I seem to recall that there is a nice quote by some (well known?) machine learning expert about too good to be true model performance. The quote is something like "If your model performance looks ...
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### Is there a certain order of steps to be taken when conducting regression analysis?

This is an extremely dumb question probably, but I took an applied regression analysis course recently and, while I feel competent enough to do regression analyses on a basic level for future projects,...
527 views

### Proper regression for determining correlations between derivatives of functions

Say we have a permanent-magnet DC motor that roughly obeys the system equation $\ddot{x}(t) = \alpha \dot{x}(t) + \beta u(t) + \gamma$, where $x(t)$ is the displacement of the rotor, and $u(t)$ the ...
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### Clarifying the applications of Bayesian networks

I have been looking at Bayesian networks, using the book by Koller, Probabilistic Graphical Models. The book is very large, so I might have missed the answer to my question ;). But I was trying to ...
• 1,522
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### Calculate probability density by function application

let's assume we have a probability density function which is $$f(X) = \frac{a}{x^a+1}$$ how can we calculate something like this: $$Y = ln(X)$$
31 views

### Which field of science applies the log-normal sample median distribution?

Which field of science applies the log-normal sample median distribution (i.e. the sample median distribution with samples from a log-normal parent)? I noticed that incubation periods are assumed log-...
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1 vote
47 views

### How to use a p-value sampling distribution?

As part of my research I have been looking into the sampling distribution of p-values. Even though p-values are on their way out, they are still used ubiquitously with the normal $\alpha$ =.05 cutoff (...
66 views

### Example of "alternating" mass function for discrete distribution

My question is related to this question on Math.SE where it was shown that there exist discrete distributions with probability mass functions that "oscillate" in a non-monotonic way over an ...
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174 views

### Potential applications of a result (by Beyer et al) on distance concentration and meaningless nearest neighbors in high dimensions

My question is motivated by this question, and self-study of the paper "When is nearest neighbor meaningful?", where the authors show the following Theorem 1: Let $X^{(d)} \in \mathbb{R}^d$ ...
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### Psychology books FOR Statistics students

I can find a lot of book recommendations on Statistics for Psychology students. But can anyone suggest some good books for a Statistics student who wants to learn about applications of Statistics in ...
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1 vote
87 views

### What is "LASSO aggression"?

I found a paper that stated in the methods section that they ran "LASSO aggression". At first, I thought it was a funny typo but then I did a Google Search: Google search and found 187 sources ...
1 vote
187 views

### Independence of censoring time $C$ and event time $T$ for randomised entry to a study

While reading through the textbook 'Modern Applied Statistics With S' by Venables and Ripley, I came across the following paragraph detailing the different types of censoring possible when dealing ...
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### Productionize (applied) PCA to detect outlier etc. long term with new data?

I was wondering how one could use PCA in e.g. a dashboard for non Subject Matter Expert. For example, you are quite certain that 2 PCs are sufficient based on the current data. It also makes sense for ...
1 vote
21 views

### Web application with model results for use in healthcare?

Often in medicine we use scores, so the patient gets 1 point for this symptom, another for this etc. and a final a score determines their risk/treatment strategy. If we have reliable data and build a ...
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### How biased is a statistical study in which sampling was purposely made without repeats? [duplicate]

[Cross posted on Math.SE] It is understood in mathematical statistics that a sample (as in sampling distribution) may very well contain repeatedly the same item/subject. In practice though, it would ...
226 views

### Are sampling distributions of any statistic used in real life statistical analyses?

I feel I am pretty good on the mathematical basis of CLT and sampling distributions. HOWEVER: While sources like OpenIntro Statistics (Diez et al, 2019) are fairly straighforward with their actual ...
249 views

### What apples do worms prefer? [closed]

I'm confused with some practical statistical problem, for which I have limited data and don't understand how to start with the problem. If anybody can point how such problems are (traditionally) ...
5k views

### Can someone provide a brief explanation as to why reproducing kernel Hilbert space is so popular in machine learning?

I thought functional analysis was long thought to be old fashioned and generally a dead research area. It seems that all of a sudden there is a huge fascination with so-called reproducing kernel ...
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### Interpreting ANOVA results in the educational context

I have run an experiment in a six-week course to measure the effect of my educational treatment on student engagement. The treatment happens on weeks 4 and 6 of the course (for all of the students) ...
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### Why should we study copulas? [closed]

I am new to the study of copulas and I would like that someone could provide some examples where they are applied, their usefulness and so on. Any help is appreciated. Thanks in advance.
40 views

### Summarize regression results on different datasets

I have 20 datasets (extracted from 20 different software systems) and fit a logistic regression model on each of them. On every dataset, the model was the same (same dependent variable and the same ...
2k views

### Evidence for man-made global warming hits 'gold standard': how did they do this?

This message in a Reuter's article from 25.02.2019 is currently all over the news: Evidence for man-made global warming hits 'gold standard' [Scientists] said confidence that human activities ...
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### How do I measure effects over years in longitudinal panel data with individuals?

I'm working with a longitudinal panel dataset that surveys the same few thousand individuals biennially and I have six years of this data. My dependent variable would be how much individuals spend on ...
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### How do I learn when to apply which statistical distributions? [closed]

I am learning Bayesian modeling and having trouble keeping straight when it is most appropriate to apply the various statistical distributions beyond the basic ones like the beta, binomial, and ...
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### What does this paper mean by mean square error?

I'm reading a paper about estimating fetal weight by ultrasound and other techniques. In Table 2 they give descriptive statistics, to wit: of all the examiners, the one with the highest mean square ...
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1 vote
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### Do you know of business applications of Reinforcement Learning?

I'm looking for literature on the application of Reinforcement Learning (RL) algorithms in a business context. Most articles and examples in books on RL are about the application of RL to games (...
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### Variables common to all individuals in a panel

I have been tasked with evaluating the efficiency of different marketing tools for a microfinance bank. I have a panel of seven individuals (seven districts of Tajikistan) over 17 months. Dependent ...
500 views

### What modeling problem does ridge regression solve?

If your modeling problem is that you have too many features, a solution to this problem is LASSO regularization. By forcing some feature coefficients to be zero, you remove them, thus reducing the ...
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197 views

### Testing the scope of application of a logistic regression model

My aim is to assess whether I can apply a logistic regression that was fitted on a sample A (where I have explanatory variables and the outcomes) to a different sample B where I don't know the ...
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### Difference between Stochastic Approximation (SA) and Stochastic Gradient Descent (SGD)

I understand the intended use cases for both stochastic approximation algorithms like SPSA or FDSA, and for SGD algorithms like Adam. SPSA is intended for noisy objective functions, and Adam for ...
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1 vote
243 views

### Mixture of power-law distribution

I have two large sets A and B of (integer) numbers, both obtained with two different (and unknown) probability distributions $\rho_A$ and $\rho_B$. A (also large) set C contains a proportion $p$ of ...
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7k views

### How Do You Choose The Number of Bins To Use For A Chi-Squared GOF Test?

I'm working on developing a physics lab about radioactive decay, and in analyzing sample data I've taken, I ran into a statistics issue that surprised me. It is well known that the number of decays ...
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1 vote
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### Population proportion inference: what statistical error am I committing here?

I am struggling to understand the following paradox. Suppose we have a large population of people who exhibit different values of a trait, e.g. they are sick with different strains of a virus. ...
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### Compare the slopes of categorical data

Hello I want to compare the slopes of the linear regression lines for the following distributions of sales figures over the years 2009 to 2017. I want to compare the slopes of the regression lines - ...
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