Questions tagged [checking]

very ambiguous, try to find a more descriptive tag, like *diagnostic* or *residuals* or *model-evaluation* ...

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Solution verification for an equation of exponentially distributed random variables

Given two i.i.d. random variables $X,Y$, such that $X\sim \exp(1), Y \sim \exp(1)$. I am looking for the probability $\Phi$. However, the analytical solution that I have got does not match with my ...
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1answer
20 views

Constant-information scale transformation

I was recently introduced to the concept of constant information scale transformations in the book Generalized Linear Model with Examples in R, by Dunn and Smyth. With that, they mention in the book ...
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115 views

Foundations behind Linear Regression / Statistical Modelling

I've always struggled with the foundations behind the concept of modelling (and specifically regression) - what is random, what is not, what we are modelling. I think I have a grasp of it - but I'd ...
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2answers
27 views

Checking of Measurement in Grouped Data

My teacher uses the formula below when looking for the median and mode of a grouped data. $$ median = L_m + c\frac{\frac{n}{2} - F_{m-1}}{f_m} \\ mode = L_m +c\frac{f_m - f_{m-1}}{2f_m-f_{m-1}-f_{m+1}...
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1answer
269 views

Naive bayes computation of denominator

I'm wondering about the denominator in this computation : ...
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2answers
273 views

Using statistics to check plausibility

I saw what seemed to be a crazy claim, that a certain parameter was small. I found a list of studies on the relevant subject and picked the one which appeared to measure the smallest value for that ...
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32 views

How to interpret a simple indirect effect obtained from two separate regressions

I have a simple question to check my math. Consider a logistic regression, Model 1, which I'll discuss in terms of probabilities rather than logits to make things simpler. All variables are binary ...
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1answer
57 views

Concerns about data for regression model

I'm building a model that predicts goals scored based on the defenses that a player faces. From the classes I've taken, you should normalize the response variable. Here is the issue I'm facing: the ...
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1answer
4k views

What is posterior predictive check, and how I can do that in R?

I am using Bayesian hierarchical modeling to predict an ordered categorical variable from a metric variable. For example, I want to regress Happiness (in 1-5 ratings) on Money (a metric variable): ...
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147 views

Model checking versus posterior predictive checks

I am interested in knowing if there are any difference in modeling checking versus posterior predictive checks in the Bayesian framework. Are posterior predictive checks a type of model checking?
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1answer
1k views

Is the linear probability model generalisable to ordered logit/probit regressions?

I have a set of data where the dependent variable is an ordered response with 7 levels and I've fitted an ordered logit model to the data, and now I want to conduct some robustness checks on the ...
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Most efficient way to check answers to exercises when learning from a statistics textbook?

There's a community wiki at: Free statistical textbooks that has a nice list of freely available textbooks on statistics. Many of the textbooks that people suggest have exercises at the end of each ...
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1answer
163 views

numerical measure for an ordered list

At the end of every semester I have to input my students' grades into a database. Typically this means I go one by one down my list of grades from my excel spreadsheet and manually fill the grade into ...
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1answer
882 views

Does a strong checksum provide reasonable assurance of absolute data integrity?

Does a checksum ensure absolute data integrity? That is, if a piece of data several gigabytes long changes a single bit, the odds are dependable that the checksum will be different, particularly with ...
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170 views

How to check a similar question in a survey

I have a survey in which I asked, "Would you be ready for a t-shirt shop in St Jean Avenue? [yes/no/don't know]". Then I asked many other questions, ultimately including, "Would you be ready for a t-...
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1answer
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What is a good academic citation for cross-validation?

I performed a holdout cross-validation analysis on a multilevel model fit. The purpose of this was to show that we didn't have a problem with over-fitting, for which it worked just fine. Now we are ...
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What are some quick initial tests to check the quality of a new dataset? [duplicate]

Possible Duplicate: Essential data checking tests When you are presented with a dataset, what are some quick things you can look for to get a feel of how 'good' the dataset is. ('Good' in the ...
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9k views

How to find duplicate cases in a large dataset?

I have a large dataset which is made up of responses from 600 shoppers on 15 variables. When I tally the responses, it comes to 603. I know there were 600 respondents, so I must have recorded the ...
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2k views

How to calculate derivative of the contractive auto-encoder regularization term?

Setup I found a paper on that has a varient on normal auto-encoders (contractive) which for its gradient uses the following regularization penalty: $$\left|\left|J_f(x)\right|\right|^2_F = \sum_{ij}...
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Essential data checking tests

In my job role I often work with other people's datasets, non-experts bring me clinical data and I help them to summarise it and perform statistical tests. The problem I am having is that the ...