Questions tagged [methodology]

For questions about statistical methodology or choice of statistical methods.

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What should I do about this question? [closed]

We are submitting a paper and the reviewer asks the following questions: It's fascinating to notice the association between d-dimer and samples discovered with MPs rather than undetected ones. ...
zhiheng yi's user avatar
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Time varying covariates in dif in dif

I'm working on a dynamic Difference-in-Differences (DID) analysis to assess the impact of child care leave on individuals' wages over their working life. My database includes information on the date ...
Andres Jimenez's user avatar
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What is a good real-life example of using correctly the Neyman-Pearson hypothesis testing framework?

I've read a couple of theoretical explanations of what it is (in particular this thread: When to use Fisher versus Neyman-Pearson framework?), but so far I didn't find real-life examples of people ...
Coris's user avatar
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(Quantitative) research methods for collocation analysis in corpus linguistics?

I am trying to conduct a collocation analysis. This is a corpus linguistics research, doing so require me to test statistical significance using Mutual Information, as well as frequency normalization ...
pindakazen's user avatar
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Doubt on non-parametric ANCOVA with two groups and pre-post scores and pre scores (baseline) as covariate

I have used a non parametric ANCOVA to analyze scores of a questionnaire (BSCS) with factors: Type of intervention(A and B) and timepoint (pre- and post) as well as baseline (same distribution as pre-)...
Fil's user avatar
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8 votes
3 answers
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What's the point in studying moderation effects if effect sizes are so small?

.002 is the median and 0.009 is the average moderation effect size in psychology, based on Aguinis et al. 2005, Effect Size and Power in Assessing Moderating Effects of Categorical Variables: A 30 ...
GT87's user avatar
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Having trouble with my analysis. I have no one to ask. I thought I would post here

I performed an experiment where I shocked fish eggs at different times prior to first cellular cleavage, this was to create tetraploid fish larvae. I have a control group and then 9 treatments (60, 65,...
LUUPE's user avatar
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4 votes
3 answers
455 views

Reducing threshold p-value in case of statistical tests following data exploration

Imagine, I got a new dataset. I look into it, trying to find a plausible hypothesis. During this I build charts, trying to find something interesting. Should I reduce the p-value threshold due to ...
Konstantin Solomatov's user avatar
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Is it valid to add more data to a training data set after evaluating on a test set?

I'm working on a machine learning project to find particular key points in images. To do this, I'm using a U-net like architecture and treating it as a regression problem to produce a heat-map of ...
ocharles's user avatar
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2 votes
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What method should I use if I want to estimate proportions in a 2xc contingency table (where c >2)?

This is a theoretical question, but it's been in the back of my head for a while now. Let's say I have two groups A and B, and I already know that they differ relative to their distribution on a ...
Daniela's user avatar
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Best Analysis Method on Understanding the Driving Factor of Math Scores: PCA?

I'm looking to understand the best way to understand the factors that drive student math scores. I have each data such as (not limited to) demographics, parent's education level (categorical), taking ...
user398656's user avatar
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Notable changes when modeling unevenly univariate spaced time series as an evenly spaced multivariate time series?

When attempting to model univariate data (although, this could easily be extended to the multivariate case) that is unevenly spaced over time, a natural approach to be able to apply common time series ...
QMath's user avatar
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What is the difference between a repeated cross-sectional survey design and a trend survey design?

Most of the references I have checked for repeated cross-sectional design and trend design (a type of longitudinal design) have said that they are one and the same. However, my professor says that ...
abetebatebs's user avatar
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Input/References on time series modeling/prediction without assuming stationarity

I am trying to find out what methodologies there are for analyzing/modeling time series without assuming the time series is stationary/trying to make the time series stationary. I am wanting to do ...
QMath's user avatar
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SEM : covariates and methodological questions regarding model simplification

I am new to SEM and have some methodological questions. Here is the model I would like run (LV = latent variable and OV = observed variables). First, from the example I saw on the web, gender, age ...
Adeline Lacroix's user avatar
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Aggregate predictions to generalize on large scale

I actually work on medical datas to predict outcome after treatment on patients with metastasis lesions of carcinomas. Each patient have different number of lesions with some with like 30 lesions and ...
Nicolas's user avatar
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p-value for results of sub group analysis with ML?

I developed a ML algorithm (Xgboost) to predict a target in my data set. I obtain here the results of my predictions on my test set : ...
Nicolas's user avatar
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11 votes
4 answers
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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 ...
QMath's user avatar
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mlr3 : Benchmark different features selection methods

I have a simple question concerning my methodology. I'm building some algorithms of machine learning to predict a binary outcome, using mlr3. I optimized my different learners (svm, ranger, glmnet, ...
Nicolas's user avatar
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Inference on Unlabeled Data in Semi-Supervised Learning and Determining Dataset Size

In semi-supervised learning, when a portion of unlabelled data is combined with labelled data during the training process, I'm wondering how one can perform inference specifically on the unlabelled ...
a_long_road_ahead's user avatar
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How to represent varying reliability of ratios calculations in a dataset?

I want to predict whether the client will renew his/her subscription based on groceries consumption patterns. Suppose an order contain only one type of grocery. I have a DataFrame containing ratios of ...
a_long_road_ahead's user avatar
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How to compare relative weight of two subsets?

For one experiment, I have two data sources A and B contributing data points, and a function that takes the union of the sets of datapoints and assigns a quality weight to each point. I'm trying to ...
John's user avatar
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Differing Time Periods for Application of Predictors in Classification Model

I am attempting to classify people as pregnant or non-pregnant. The business case requires that someone be considered in the model if they meet certain criteria (morning sickness, missed ovulation, ...
Englishman Bob's user avatar
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Is there an issue doing EFA first, followed by a cluster analysis (with the newly found factors) with the same sample?

We want to compute a cluster analysis in a not well-researched field and therefore created about 60 questions. Those questions are supposedly aspects of factors, but we are not sure yet, to which ...
Tim's user avatar
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Dependent Variable Containing Multiple Binary Variables and Specifying Appropriate Model Type

I am attempting to make a dependent variable that contains 4 survey questions that are all binary responses. I am unsure what the best way to go about doing that is potentially through a type of index....
tangypancake4512's user avatar
7 votes
2 answers
380 views

Is pretraining on test set texts (without labels) ok?

Edit: after skimming this paper6, I narrowed the scope of this question to NLP problems. Relevant excerpt from the abstract (emphasis my own): We demonstrate that unsupervised preprocessing can, in ...
chicxulub's user avatar
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Can I use Independent component Analysis on features extracted from a single timeseries?

Consider this simplified situation: I have a single time series and from that I compute a set of parameters (e.g. mean and variance). These parameters are however not independent from one another (e.g....
Luca's user avatar
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Statistical significance of the difference between two regression models [duplicate]

How to test the difference between prediction accuracy of two regression models? My idea is to compare the errors of the two models, e.g., one-predictor vs. multiple-predictor model, in order to show ...
Mikolaj Buchwald's user avatar
1 vote
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29 views

Normalisation methodology and batch effect

I have a question about the normalization of datas and batch effect ... For example, here is a dataset : ...
Nicolas's user avatar
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1 vote
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Discussion regarding a non-standard method to compare multiple groups of algorithms on different tests

TLDR: I am trying to compare groups of machine learning algorithms across a set of datasets. I understand the usual methodological procedure to compare the algorithms but I believe there is a ...
Jacques Wainer's user avatar
1 vote
1 answer
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Doubt on cross-validation mean error value for a neural network

At the end of the cross validation of a multi layer peceptron, do we make the mean of the validation results of the last epoch of the model on each fold or do we make the mean over all the errors? For ...
PwNzDust's user avatar
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2 votes
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Should a meta-analysis of group differences calculate Hedges’ G separately for each group, or calculate Hedges' G for the group difference?

I am reading a meta-analysis where the authors state the following. (I've redacted the active drug name, as my purpose is to understand not call anyone out.) The treatment response to placebo and [...
llewmills's user avatar
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1 vote
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Validity of modelling different ordinal variables via linear regression

I am attending a course in Marketing. Our latest assignment was to analyze data from a survey regarding dishwashing detergents. The questions we asked respondents were all of an ordinal kind: they had ...
ladislaw94's user avatar
2 votes
1 answer
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My data is right skewed and I don't have independent observations, which statistical model should I use in R?

I have biomass data collected at 3 different distances from 42 different ant mounds (at the edge of the mound, 1m and 4m away). In total there's 42 ant mounds, from 11 plots at 5 different elevations (...
SofiaIréne's user avatar
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102 views

Time Varying Difference in Differences Model

If I am looking at the impact of different tariffs in different months on exports, can anyone tell me if this would be the correct difference in differences model? Or would it be
kz500's user avatar
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1 vote
1 answer
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What is the difference between validity testing and actual results?

Researches usually present the results of validity tests conducted before the actual results - these include descriptive statistics with Mean and SD and also inter-construct correlations. Then there ...
helpjpls's user avatar
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How to create optimal observation given a classifier

Suppose that I have a dataset $D$ of cars and a classifier $C$ which, given two cars characteristics, predicts which car is "better". (It's a binary classification, the definition of better ...
nprime496's user avatar
1 vote
1 answer
29 views

Can a model overfit on feature position? [closed]

I am doing a project about predicting which car will win a race given car characteristics as well as road characteristics. I use features corresponding to those : my model takes car1 features, car2 ...
nprime496's user avatar
3 votes
1 answer
47 views

Classification Method with Small Data

I have the following problem. I have individual observations $y_i \in [0,1]$ on the response to an increasing stimulus called $x$. The stimulus is discretized as $x^1, x^2, \ldots , x^n$. Let's use ...
deps_stats's user avatar
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1 vote
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How to model multinomial output given one categorical input?

I have climate and vegetation data by latitude longitude. The vegetation data is a categorical variable with 20 possible options. The climate data is relative frequency of occurrence (RFO) for a dozen ...
The_Tams's user avatar
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Is this a meaningful method to determine spread around mean?

I have student ratings of 123 schools across the US. They represent 100% of this type of school across the US. The ratings are on the scale Poor, Fair, Good, and Superb, and I have the number and ...
Logan_Stat's user avatar
4 votes
1 answer
3k views

Is reporting univariate regression next to multivariate regression acceptable methodology?

In a paper published in Ebiomedicine (part of the Lancet family journals), the researchers built a logistic model including a variety of predictors and then reported both "univariate" ...
outofthegreen's user avatar
3 votes
1 answer
4k views

Long-term event study vs. difference-in-differences (DID) analysis

I am trying to understand the differences between event studies and DiD analysis. In particular, if I want to estimate the specific effect of an event like certification adoption, CEO appointment, or ...
Matteo's user avatar
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Which method of logarithmic transformation is correct to use in linear model?

I try to do a simple linear model with logarithmic transformation of y values. I found that depending on which method I use the results differ and I don't ...
Natalia's user avatar
1 vote
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88 views

Why is internal consistency a measure of reliability?

Why is 'internal consistency' a measure of reliability? It looks like a measure of validity instead. Definitions: "Internal consistency reflects the extent to which items within an instrument ...
Glue's user avatar
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-1 votes
1 answer
51 views

Did D. Paul Sullens use proper methodology in his 2016 study on the children of gay parents? [closed]

When the study "Invisible Victims: Delayed Onset Depression among Adults with Same-Sex Parents" was released, a rebuttal was soon posted. Sullens posted a counter which stated at the end: I ...
Jacob Blaustein's user avatar
1 vote
1 answer
141 views

How to deal with bias caused by data collected with different methods on a GLM?

I have two datasets from different years (2020 and 2021) that I needed to merge because my sample was too small. I'm investigating which morphological features (sex, age, weight, fat reserves and ...
Kate's user avatar
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I’m trying to find the association between 2 variables by conducting a statistical test

My two variables are sex (male/female) and body mass index (BMI). I have a data set of 194 participants. Sex - 107 males (55.15%) / 87 females (44.85%) BMI - 23.88 +/- 5.03 I have no idea which test ...
Mysticoug7 's user avatar
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13 views

How can I use the trend of a graph to plot the next point?

I created a hypothesis for a chemistry assignment and then conducted an experiment. The experiment resulted in a graph that had a downward trajectory. It looked like this: I found the data points by ...
user avatar
1 vote
1 answer
42 views

Combining multiple time series with unknown start dates

I have a small database of voltage information from multiple batteries (of the same type), with each measurement being a tuple of (battery id, battery voltage (as a percent) and measurement time). I ...
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