0
votes
0answers
2 views

Problem with Mann-Whitney U test in scipy

I am trying to perform Mann-Whitney test on a real data set using scipy. I extracted an example where the problem occurs. It seems that the function tiecorrect returns negative value which is the ...
0
votes
0answers
2 views

Generate mixture model from data with features

I want to build a mixture model from my data, but using features of my data to calculate each component in the model. The data: For each point I have 34 associated features. Each feature is a boolean ...
1
vote
1answer
5 views

Draw a multinomial distribution from a Dirichlet distribution?

I have a very rough understanding of the Dirichlet distribution and already seen some visualizations of its pdf over the 2-simplex, i.e., $\alpha$ is a 3D vector. However, I still do not understand ...
0
votes
0answers
6 views

Best way to examine mortality tables?

I have a set of tables containing mortality rates (hazard rates) and I want to see how well these values reflect the influence of the covariates (age, sex, issue year, etc.). I also have actual ...
0
votes
0answers
3 views

Variance functions and transformations in linear mixed models, beginner questions

First post here. I'm pretty much a newbie both in statistics and using R, but nevertheless trying to fit a linear mixed model with the package nlme. My question is about transformations/variance ...
0
votes
0answers
4 views

Number of inputs used by ARIMA model

Should be an easy question but Google failed me. When using ANN for series forecasting one often uses may variables. For instance the number of shoppers might be determined by the previous number of ...
0
votes
0answers
5 views

Variance and asymmetry on relative frequency class distribution

I don't know how to resolve this (easy) exercise. I've calculated the first output. But I don't know if it's correct. Calculate arithmetic mean, variance (standard deviation^2), concentration and ...
1
vote
0answers
5 views

Marginal pseudo-likelihood and consistency?

For a given set of random variables, $X_1,...,X_n$ we know that in many cases finding the maximum of the pseudo likelihood: $$PL(x_1,\ldots,x_n) = \prod_{i=1}^n p(x_i | ...
1
vote
0answers
2 views

Bias-variance decomposition with sklearn BaggingRegressor

There is an example given on the Scikit-Learn site that compares the bias-variance decomposition of the rmse of a single SVR model against a bagging ensemble. Unfortunately, the data is being ...
1
vote
0answers
6 views

Survey Sampling Question

Question: A Secretary of State wants to survey the primary owners of motorcycles registered in the state to estimate the proportion who want the license plates redesigned. (Primary owner means that ...
0
votes
0answers
2 views

How to test data migration quality on very large sample set

I am migrating 2M individual bio-specimens from one IT application to another (sample location data, 5 levels). While the data migration tools are "validated", I want to create a statistical model to ...
0
votes
0answers
2 views

which distance should be used with UPGMA clustering

I am trying to cluster a biological population on the basis of morphological characters using UPGMA clustering method, but I am not sure which distance should I use- Mahalanobis or Euclidean. What are ...
0
votes
0answers
12 views

predicting time series with support vector machine using R

I am planning to do time series prediction using support vector Machine. I could not find any materials about time series application of support vector machines using R or Mat-lab. Similar question ...
0
votes
0answers
11 views

Estimate the covariance matrix of a normal distribution if the mean vectors is given by a linear rule

Let $X=(x_1,\ldots,x_n)^\top\in\Bbb{R}^n$ be a random vector that follows a multivariate Gaussian distribution with known mean vector $\mu=(\mu_1,\ldots,\mu_n)^\top\in\Bbb{R}^n$. The covariance matrix ...
0
votes
0answers
7 views

vif output for multicolinearity when you have factors

using vif(model) in R provides us with the variance inflation factors for out model. often people use sqrt(vif(model)) > 2 ...
0
votes
0answers
12 views

Appropriateness of ANOVA after k-means cluster analysis

The notification after the ANOVA table after K-means analysis indicates that significance levels should not be looked at as the test of equal means, as the cluster solution has been derived based on ...
0
votes
1answer
30 views

Questions regarding Binary Logistic Regression

I am very new to statistics and is currently performing binary logistic regression analysis to test null hypothesis for my dissertation. First, both my independent variables and dependent variable ...
-1
votes
0answers
11 views

Sample size for ANOVA

Is there minimum sample size for each group in 1-way ANOVA? if yes, please give a reference(s), If no, why there is not?
0
votes
0answers
4 views

Effect sizes for post-hoc paired comparisons in one-way ANOVA

Is there any alternative (like Cohen's d in t-test) to report about effect sizes for post-hoc paired comparisons in a one-way ANOVA (3 factor levels, correlated samples)?. Many thanks!!
6
votes
1answer
52 views

Permutation tests: criteria to choose a test statistic

I regularly use permutation tests and love their simplicity. I've learned most from the book "Resampling methods" by Good, in which the author seems quite creative in his choice of test statistics ...
0
votes
0answers
5 views

Contradictory results in GEE with or without a covariate

Three independent variables, one is between-group with 2 levels, the other two are within-group with 2 and 4 levels respectively. Another continuous variable (IQ) is controlled as a covariate. The ...
0
votes
0answers
16 views

Best way to analyze road accident data

A dataset having accident details has been posted on this site: https://wiki.csc.calpoly.edu/datasets/attachment/wiki/HighwayAccidents/ACCIDENT2007-FullDataSet.csv (from: ...
0
votes
1answer
21 views

Probability of a sum of values from a number of dice rolls

4 six-sided dice are rolled independently. Compute the normal approximation with continuity correction for the probability of rolling a total of at most 6. I have arrived at a point where I got that ...
0
votes
0answers
14 views

Analyses of mixed variables

I'm relatively new to statistics, and am currently working some data collected as a part of an interview survey. I have a response variable in ordinal form, which mostly looks into people's ...
0
votes
0answers
15 views

What is the relationship between naive Bayes and Mahalanobis distance

Recently, I found a code project which uses the Mahalanobis distance to compute Bayes value, but I don't know why you can do that. Second, as I know naive Bayes is based on the Bayes rule, and how ...
0
votes
1answer
27 views

NA produced in linear regression model

I have read similar posts to this but my problem is not resolved by the answers given. I want to do a v simple linear regression to see if bite incidence is related to district, zone (vacc or control) ...
0
votes
0answers
34 views

calculate probability for passengers who caught with gun [on hold]

Can someone please give some clue? One strange phenomenon that sometimes occurs at U.S. airport security gates is that an otherwise law-abiding passenger is caught with a gun in his/her carry-on bag. ...
0
votes
0answers
39 views

what is true about s zscore [on hold]

What the relation between score and mean, median? whihc is true from this ...
0
votes
0answers
7 views

getting posterior probability of the hypothesis of hypothesis

At any given time about 5.5% of women (age 15-45) are pregnant. A home pregnancy test is accurate 99% of the time if the woman taking the test is actually pregnant and 99.5% accurate if the woman is ...
0
votes
0answers
21 views

Time series forecasting accuracy measures: MAPE and MASE

We come to this toy example showing MAPE and MASE are not consistent when measuring forecasting accuracy. Data consist of 100 white noise and 100 $AR(1)$ time series with length $N=500$, mean $\mu=1$ ...
0
votes
1answer
6 views

how do I test the relationship between infection and nurse:patient ratio

I am evaluating whether the prevalence of a specific infection in the ICU bears a relationship to the nurse:patient ratio over time. The infections are whole numbers (nominal variable)and the nurse: ...
2
votes
3answers
48 views

Specific Hypothesis

I have one sample group. (I know my test statistics is nonparametric.) My null hypothesis is a CI and alternative is ~ . What is your idea for testing this hypothesis?
0
votes
0answers
13 views
0
votes
0answers
21 views

demostrate Jensen's inequality (i think)

Please any help is very good. I was trying to start with the definition of expected value but I don't know how to finish.
3
votes
1answer
19 views

How is it meaningful to give fitted values for random effects if they don't appear in the likelihood function?

Software for fitting random effects models tends to output values for the random effects. For example, suppose the model is $$y_i = \alpha_i + \varepsilon_i, \qquad 1 \le i \le n$$ where $$\alpha_i ...
0
votes
0answers
1 views

positive residuals after standardizing predictors in gls using R

I am using generalized least square in R. The original data I have seems to be OK when fitted with gls (judging from the residual vs fitted value graph). However, since I want to compare across ...
1
vote
2answers
26 views

Difference between identity and diagonal covariance matrices

thanks in advance for the help. Suppose I am training a linear model. What are the conceptual differences between using a diagonal covariance matrix and the identity? It is clear to me that the ...
0
votes
1answer
20 views

Test for correlation between continuous and categorical variable [duplicate]

I am wanting to know what type of statistical test would need to be carried out to determine if there is a correlation between one categorical variable and one continuous variable.
1
vote
0answers
20 views

High negative correlation between intercept and slope

I was trying to fit several mixed linear models, however for 2 (out of 4) I am getting quite strange results. The point is that I've collected data from two courses (a few students were the same in ...
2
votes
0answers
12 views

Error of bounded mean estimation with quantization

I have a distribution whose mean $\theta \in [0,1]$. Given $n$ observations, I compute the sample mean (say $\hat{\theta}$) and quantize it to accuracy $\frac{1}{n}$ (basically I can use only ...
1
vote
0answers
18 views

In Probabilistic Graphical Models, what does it mean that r.v. X influences r.v Y?

I wanted to pin down what the intuitive phrase: r.v. X influences r.v. Y as precisely and as rigorously as I could, and wanted to check if my interpretation was correct and complete with the ...
0
votes
0answers
25 views

Calculating probability of full house and royal straight in R poker simulation [migrated]

Given a poker simulation in R using vectors for the denomination and class of playing card in a loop, how would one go about identifying a given hand containing a full house or a royal straight. I'm ...
2
votes
1answer
68 views

Regressing out a variable?

What exactly does it mean to "regress out" a variable or quantity? This is something I hear about all the time, but it's strangely difficult to find a precise description online. Any pointers - ...
1
vote
0answers
14 views

How do I filter insignificant modes from a kernel density estimation

How do I detect the number of significant modes in a set of data? I have a set of 1 dimensional data where the number of modes are unknown. I'm familiar with python and scikit learn so I use the ...
-1
votes
0answers
14 views

How do I solve problem 1. c) in the following link? (Marginal Probability) [on hold]

https://moodle.concordia.ca/moodle/pluginfile.php/1785520/mod_resource/content/1/Assignment%201.pdf It seems as if I need to find the mean of the marginal distribution table, but I do not know what ...
1
vote
0answers
33 views

disadvantages of Neural network method

Hello Dear Researchers! I want to list the advantages and disadvantages of Neural network methods for classification or estimation purposes. I have already found the advantages of NN method in many ...
-3
votes
0answers
33 views

Interactions in regression [on hold]

Consider a multiple regression model with gender as one of the predictors. Suppose gender has no significant effect in this model. Is it possible that an interaction of gender with an independent ...
0
votes
0answers
7 views

Are there any packages to calculate accuracy, precision, recall and f-measure achieved by a KNN-classifier in R language? [on hold]

I have been trying to find packages to find accuracy,recall, precision etc performance metrics for the KNN-classifier. The closest I could find was caret but it says the object in its parameters has ...
1
vote
0answers
19 views

Sufficient and complete statistic

Let $ X_1, ... , X_n $ be i.i.d random variables with pdf given by $$f(x;\theta) = \exp(-(x-\theta))I_{(\theta, \infty)}(x)$$ It is asked to find a sufficient statistics for $ \theta $ and to verify ...
2
votes
0answers
15 views

Normalized RMSE

I have several time-series in a VAR(1) and, due to some of them haven't the same unit of measure, I'd like to estimate the RMSE in percentage. I know that it could be done in several ways (see below) ...

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