# All Questions

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### Influence of TV spots on the number of visits to the website (time series problem)

I have hourly data regarding the number of visits to the website. A single record consists of date, time(0-23) and number of visits. In a separate table I have data about the display of advertising ...
12 views

### NLP Classification over Taxonomy [closed]

I have a massive pool of data where each row maps a user-entered description to a code that classifies the mission that the description describes. I am trying to develop a model that at least helps ...
7 views

### taking the radius neighborhoods of the points and joining them With R [closed]

I am trying to create the codes for the image below in R but failed. In short, we create their neighborhoods by taking certain radii on the points. then we connect the neighborhoods with the correct ...
24 views

### Sample size needed for a survey with multiple questions

I want to make a survey with several questions and conclude those results for the whole population. For example, I want to estimate the following questions for my 1 million population : "do you ...
16 views

### Can I conduct a weighted regression if I have one observation per year?

I am conducting a word analysis project where I find the relative frequency of a certain word over time in a corpus of film reviews. The corpus changes in size over time so someone suggested to me ...
27 views

### How to determine if 2 specific variables should be in the regression at the same time [closed]

I am trying to run a regression and I have two variables; income and gender. How can I determine if these 2 regressors should be in the model at the same time? Is there some sort of a test?
17 views

### numpy eigenvector and eigenvalues not making sense [closed]

sorry, maybe the subject is too strong? but its driving my little brain crazy ..please look at the code below ...
24 views

### Is it preferable to subset data to test specific hypotheses or specify a full model and run contrasts?

Let's say I have a 2x2 design where participants are either in condition A or condition B and, within each condition, either get exposed to exposure C or exposure D. First, I want to test whether ...
24 views

### Correlation between nominal and ordinal variables

In my survey data I have two variables: One is an ordinal variable with 5-scale scoring from Agree to Disagree. My second variable is an nominal variable where the participants had to choose from 7 ...
8 views

### LR test for overlapping return data using bootstrap

I wish to test a null hypothesis as in Christoffersen (1998) to see whether a sequence of Value-at-Risk forecasts $Q_t(p) \in \mathcal{F}_t$ possesses correct conditional coverage. Here $p \in [0,1]$ ...
26 views

### Expectation and variance of order statistics (x(n)-x(1))

I saw a solution for Expectation and variance of range (x(n)-x(1)) uniform $\mathcal U(0,\theta)$ from Ben. Namely: $$f_{R_{n}}(r)=\frac{1}{2θ}⋅Beta(r2θ∣n−1,2)$$ From this expression, we get the ...
15 views

### Using both fixed effects and random effects in r metafor package

Hi there :) I am trying to run a meta analysis using rma.uni in the metafor package in r but cannot work out how to add both fixed effects (eg bird migration status) and random effects (eg species, ...
24 views

### Can I use a binary logistic regression for repeated measures data?

For this particular study, I had 3 monkeys complete 3 tasks, each task has a binary outcome (Win/Lose). A task is considered complete when they reach a criterion of 85% accuracy in their most recent ...
16 views

### Interpreting classification metrics for multiclass imbalance

I am at the point of reporting my results in a research article conducted. The dataset is highly imbalanced with class 1 and ...
13 views

### How to interpret cokurtosis results?

I calculated a cokurtosis matrix of the returns of multiple stocks. I obtained the following results but not sure how to interpret them. I understand that when two random variables exhibit a high ...
58 views

### Poor classification performance on a balanced dataset

I am trying to build a Stock Trend Prediction model (Target variable is 1 if the price goes up the next day and 0 if it goes down). The dataset consists 2724 samples and 60 features. Th data was split ...
19 views

### A question about fisher's z transformation detail of his paper published in 1921

Typically, people will use Fisher's z-transformation (arctan) to turn the r into a variable that is approximately normally distributed. When I look though his paper published in 1915(https://www.jstor....
14 views

### What model should be used for vector to scalar time series prediction

I'm new to machine learning and I'm trying to work on a problem and the data looks like the following: ...
22 views

### Orders of ARMA(p,q) model using ACF and PACF plots

I am trying to determine a few possible autoregressive moving average (ARMA) candidate models for a time series analysis. I have decided to look at the lags of the ACF and PACF plots; however, I am ...
18 views

### Combined probabilty for 1 to 6 between a cube and a dodecahedron, not counting 7 to 12

We have two dice, one with six sides (a cube) and one with twelve (a dodecahedron) The cube bears the numbers 1 to 6. The probability for each number is $\frac{1}{6}$. The dodecahedron bears the ...
19 views

### What does a straight line of residuals of a time series mean?

I used Python's statsmodels' seasonal_decompose & received the following plots: I understand that the residuals here are what is leftover after trend & ...
4 views

### Ordinal package - CLM. Too many variables violate proportional odds assumption - what do I do?

If too many variables show nominal effects or dealing with them causes model misspecification as shown by the Hessian value, is it OK to leave them as is in the clm and say something like “on average, ...
17 views

### Measuring uncertainty with bayesian neural network

One of the ways to measure epistemic uncertainty, is using bayesian inference in neural networks. The idea is to learn the posterior over the weights $P(\phi|X)$ which describe the probability ...
12 views

### Interpreting procrustes analysis

I am trying to find out if there is a correlation between two data sets (if one of them, which is called "varechem", depends on the other, which is called "varespec"). I ran the ...
10 views

### How do I calculate the cumulative probability of an observation fitted with a mixed effects model?

I am interested in getting the cumulative probability of an observation that is fitted with a generalized linear mixed effects model. For a linear model with gaussian distribution this seems simple. (...
21 views

### How do I calculate the correlation coefficient between these two sets of data, taking into account the uncertainty values I have for one of them?

I have two sets of data, both of which have a varying pattern pattern. I believe that one set of data (in blue in my image) illustrates the cause of the pattern which shows in the other set of data (...
21 views

I'd like to know if there is a concentration inequality for the sample covariance matrix that don't assume the knowledge of the true mean. Background. Given a probability distribution $\mu$ on $\... 0answers 9 views ### Nominal effects variables - is it ok to interpret z value? Is it appropriate to report the statistical significance of the threshold coefficients for variables in a clm model that were calculated with nominal effects? Using the example from the ordinal ... 1answer 27 views ### Comparisons of distributions: How to deal with discrepancies between visual impression and statistical tests (K-S, ranksum)? I'm having some doubts how to properly compare my data (because of visual discrepancies), represented as histograms. Here's an minimal and representative example, illustrating the data: I measure BMI ... 0answers 8 views ### Update an existing ordinary linear regression with new data and another covariate I am studying a case on a topic that was studied a while ago, related to food technology. To simplify the question, let's say that there are old OLS models that relate this property ($Y$) in certain ... 0answers 11 views ### Statistical significance of increments (treatment/control) This is a very rookie question. I have data for three years (2018, 2019 and 2020) on income, disaggregated by treatment/control units. I want to verify whether the income has increased more for ... 0answers 18 views ### Find P(B) given P(A∩B), P(A^c∩B^c) and P P(A∩B^c) [closed] I have an exam question and I don't understand how they reached the answer. The question is find P(B) given that P(A ∩ Bc) = 1/3 P(Ac ∩ Bc) = 1/2 P(A ∩ B) = 1/10 I checked the answers and there ... 0answers 3 views ### linear mixed model and post-hoc comparisons I realised that this is going to be a long post. So I apologise in advance and thank everyone for taking the time. I am performing an MRI study in which I presented visual stimuli of four conditions ... 1answer 33 views ### How do you express the variogram$\gamma(u)$in terms of correlation for a stationary process? The Analysis of Longitudinal Data textbook by Diggle et al. (2002) mentioned twice (p48 f. and then on p82) that given the following definition of the variogram, \gamma(u) = \frac{1}... 2answers 49 views ### Why important features does not correlated with target variable? I'm testing if there is a relation between top important features and correlation between those features and target. I'm working on the titanic dataset. I plot the feature importance (using ... 2answers 33 views ### Model Explanation I have a problem where I am trying to predict something from historic tabular data. We have features {X1,X2,..Xn} and I have a prediction {Y} I am trying to find a way to explain why the model came up ... 0answers 7 views ### What is the difference between the receptive field and a patch? In this question and answer it is beautifully described what a patch is. What's a "patch" in CNN? However, for me, following the explanation in the link, it seems like a patch and the ... 0answers 8 views ### Where can raw data on New York's Covid-19 Vaccination be found? [closed] New York State has a dashboard of vaccination progress at https://covid19vaccine.health.ny.gov/covid-19-vaccine-tracker , but I was looking to access the raw data behind the dashboard. Usually this ... 2answers 37 views ### How to match the distribution of one dataset when subsampling from another? I have two datasets that measure the same variable under different conditions. The first dataset (d1) is much larger (9,000 observations) than the second dataset (d2; 900 observations). A histogram of ... 3answers 77 views ### Relationship between Bayes Rule and Bayesian Networks Learning about Bayesian Networks in school - I ran across a problem which ask to find the probability of$Pr(Alarm|Storm=T)$given a column of event data for four variables: Storm, Burglar, Cats, and ... 0answers 8 views ### Error message in R when applying irf function to a SVAR-model [closed] I estimated a structural autoregressive model with the following R commands: var=VAR(dat, p=2) A=matrix(c(1,0,NA,1),byrow=TRUE,nrow=2) B=matrix(c(NA,0,0,NA),byrow=TRUE,nrow=2) svar=SVAR(x, Amat = A, ... 0answers 29 views ### frequency of a word that is close to itself in a list [closed] I have 2 files where the word "test" is found 3 times each. distributed.txt this is only a test to see if test is same as test Another file has the word ... 1answer 36 views ### Intuition on Wasserstein Distance I've been trying to familiarize myself with the Wasserstein distance and saw this answer on StackExchange by @antike that at first made a lot of sense, but then it didn't (to me, of course). In the ... 2answers 22 views ### How to measure correlation between multi-item likert scales? I recently conducted a online survey and are now having trouble deciding for the right analysis method. For example: I wanted to see if there is a correlation between Factor A and Factor B. However in ... 0answers 3 views ### How to Forecast Quarterly Dependent variable with Monthly Independent Variables with Random Forest I want to forecast US GDP(quarterly variable) using 100+ monthly financial and macro variables with Random Forest. My issue is that I do not quite know how to interpolate the quarterly data into ... 0answers 36 views ### What use is a test set in a continuous training setting? I have tuned and trained a model that predicts an aspect of customer behavior from behavior within the most recent 12 months. After initial training, generalization performance was estimated based on ... 2answers 57 views ### Fitting a distribution like exponential but with always negative$\frac{d^2}{dx^2} \log \text{pdf}(x)$I have some continuous data in the domain$[0,\infty]$which I have physical reason to believe is almost, but not quite exponentially distributed. The difference between my idea of a distribution and ... 1answer 12 views ### How is Gaussian assumption used in proving Gaussian comparison inequality I'm studying the HDS book by Martin Wainwright. In section 5.4.1, there is a Theorem 5.25, which is a general Gaussian comparison inequality, reproduced as follows. Let$(X_1,X_2,\dots,X_N)$and$(Y_1,...
I am an aerospace enthusiast. I have obtained wind speed data that's been gathered and published by NCEP/NCAR. It provides wind speed data for every $2.5^\circ$ increment in latitude and longitude for ...