0
votes
0answers
5 views

ratio of standard errors

Is there a general interpretation of the ratio of two standard errors, $\frac{se\left(\hat{\theta_1}\right)}{se\left(\hat{\theta_2}\right)}$ We want the standard error to be as small as possible so ...
0
votes
0answers
4 views

Find distribution of underling feature

Let's say I have a dataset compose of value for the variable W. The distribution of W doesn't follow any obvious know distribution. I have a model that gives W as a functions of E and K. W = f(E, K). ...
0
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0answers
4 views

Concept learning

Assume you are considering an instance space of 6 binary and 1 nominal (with 3 possible values, like Rainy/Sunny/Snowy) attributes. What is the total size of this instance space X with these 7 ...
0
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0answers
7 views

In triple exponential smoothing, what is the proper formula for recalculating gamma (seasonality)?

A pretty targeted but precise question -- In triple exponential smoothing (which there are many combinations of additive, multiplicative). What is the proper formula for calculating the new ...
0
votes
0answers
10 views

Calculating Log-Likelihood from Simulated Distribution

I want to perform some sort of model evaluation of a multivariate distribution with the property that it is difficult/impossible to calculate the likelihood (of the whole model, you can do it for ...
0
votes
1answer
9 views

How to explain change of sign on regression coefficient when another variable is added to OLS model? [duplicate]

I am trying to run an OLS regression, with log of per capita calorie as my dependent variable and age and years of education of household head, log per capita expenditure as my independent variables ...
1
vote
0answers
10 views

Repeated measures or two-way ANOVA, and power analysis

A sample of patients will undergo two treatments. Every patient will receive both treatments.One treatment will on the left side and the other different treatment on the right side. Repeated ...
0
votes
1answer
13 views

Algorithm for uniform sampling with bounded replacement

Is there a simple algorithm to sample from the uniform distribution on sequences of $n$ numbers, each taking one of $m$ integer values from $0$ to $m-1$, where each value can be repeated at most $r$ ...
1
vote
1answer
27 views

Density plot of parameter estimates from linear regression model

I am running a linear regression model in R: data(iris) fit1.iris = lm(Sepal.Length ~ Petal.Length+Petal.Width , data=iris) summary(fit1.iris) These are my ...
0
votes
1answer
25 views

Mean field variational inference

In Chris Bishop PRML book p.465 equation 10.6, the derivation doesn't explain why exactly the term $\int q_j ln(q_j) dz_j $ was generated, is not that term supposed to be multiplied by constant, did ...
0
votes
0answers
14 views

Is this logit model a multilevel model, and what is the correct way to model it?

I am analyzing a sample of about 6000 actions carried out by about 500 multinational companies in about 80 countries during a 6 year period. Actions are carried out randomly, and are not longitudinal ...
0
votes
0answers
22 views

Need to know if this is right and how to calculate this.\

I need to stat the null which I think is H0: P=124 Ha: P≠124 am I on the right track? I also have to test at a 5% significance level and show appropriate test stat a P-value. The stuff we went over ...
0
votes
0answers
12 views

Anomaly detection: multivariate Gaussian distribution

I am trying to do anomaly detection on a heterogeneous dataset (There are unknown groups present in the dataset). I want to try multivariate Gaussian distribution based approach, but I was thinking of ...
0
votes
0answers
14 views

Overestimating variance with MCMC

I'm working with a very specific type of proposal distribution in MCMC algorithm. To validate it I use a simple multivariave Gaussian with $\mu=0$ and $\Sigma$ an identity matrix. The proposal ...
2
votes
2answers
45 views

Self-study: Finding the maximum likelihood estimates of the parameters of a density function

Consider a random sample $x_1,x_2,...,x_n$ from a newly-generated distribution, whose probability density function is given below \begin{equation} f(x|\alpha,\beta,\sigma)=\frac{1}{\Gamma \left( ...
0
votes
0answers
19 views

Interpreting negative binomial regression with log transformed independent variables

My dependent variables were highly skewed, so to normalise the distribution they were log transformed. Also since there were zeros in the data, I've added + 1 to transform the variables. This is what ...
1
vote
0answers
9 views

Understanding multiple KS tests

I have read these two questions Why are p-values uniformly distributed under the null hypothesis? and Understanding scipy Kolmogorov-Smirnov test And this inspired me the following experiment. I ...
0
votes
0answers
2 views

Is smooth.spline appropriate for presenting the trend of chemical concentration in a catchment

In my case,the Electrical Conductivity (EC) values are measured daily in some pints of catchment from 2007 to 2014, and around 20% data are missed, due to without probe or flux. To presenting the ...
0
votes
1answer
8 views

Dependent samples but unable to pair individual scores

We surveyed a group of students before an in-school year-long project and after, and want to see if the changes in scores are significant. Data doesn't meet assumptions of normality. Can we use the ...
0
votes
0answers
6 views

Polynomial fitting for Shading Correction

I am reading the book Optimization for Computer Vision, and the first example of optimization is a regression for shading correction, in which the author proposes the following polynomial: $p_s(c,x) ...
1
vote
0answers
28 views

Multiple Imputation - Help Needed

These multiple imputation results relate to data I have previously described and shown here - Skewed Distributions for Logistic Regression Three variables I am using have missing data. Their names, ...
0
votes
0answers
13 views

How to calculate standard deviations/z-score given a confidence level

So, I'm a total statistics neophyte, and need to calculate the number of standard deviations/z-score based on a confidence level, in javascript. I have a table which provides some data: ...
1
vote
0answers
20 views

R random forest on Amazon ec2 Error: cannot allocate vector of size 5.4 Gb [migrated]

I'm training random forest models in R using randomForest() with 1000 trees and data.frames with about 20 predictors and 600K rows. On my laptop everything works fine but when I move to amazon ec2 to ...
0
votes
0answers
12 views

Scaling data constrained to be varying between a floor and ceiling set of values

I have data that range continuously between the values of 0 and 2, usually somewhere in between close to 1 on average. 0 is a "floor" and 2 is a "ceiling." The data describe more than one group of ...
0
votes
1answer
20 views

Minimum sample size for 1 way ANOVA?

I have tested a group of participants over various time points and I want to investigate whether mean score on each subsequent time point is significantly different to the mean score at baseline (eg. ...
0
votes
0answers
24 views

Find the radius of a cluster, given that its center is the average of the centers of two other clusters

I do not know if it is possible to find it, but I am using Kmeans clustering, and I am stuck to the following. In my implementation, I create with two different threads the following clusters: ...
0
votes
0answers
22 views

Kruskal–Wallis non-parametric alternatives for groups with different shaped distributions

My question does't duplicate this question, even if the titles are nearly similar. The Kruskal–Wallis test "assume that the observations in each group come from populations with the same shape of ...
0
votes
1answer
14 views

How many hypotheses are needed when researching one category with multiple likert-scale question

I am currently researching two groups on their willingness with 5 questions on a 7-point Likert-scale. My hypotheses are: $H_0$: There is no difference in willingness between the two groups. $H_1$: ...
0
votes
0answers
10 views

Clusters as input for classification

I'm currently performing clustering as a batch job and then in real time I'm assigning new points to cluster whose centroid is closest to new arrived point. The other approach that I see is to ...
0
votes
0answers
19 views

Modeling continuous abundance data with a GLM in R: how to select the correct distribution family?

I have abundance data (counts) that I have standardized by area sampled, making them continuous. I would like to explain them with my two independent variables using a GLM but I am having trouble ...
3
votes
2answers
91 views

Skewed Distributions for Logistic Regression

I have been developing a logistic regression model based on retrospective data from a national trauma database of head injury in the UK. The key outcome is 30 day mortality (denoted as ...
1
vote
2answers
20 views

What means “CDF of one group does not cross the CDF of the other” from the dunn.test description? [duplicate]

From the dunn.test manual: "CDF of one group does not cross the CDF of the other". What this means? I am not a statistician, but I want to understand. What I found ...
3
votes
1answer
59 views

Does the birth date of professional boxers matter? Prove/disprove what an astrologer might predict

As a followup to my question about the birth month of boxers, I am posing the fundamental question along with my hypothesis (testing if there is any truth to a conclusion an astrologer might make): ...
4
votes
1answer
40 views

Has the free kick spray in soccer an effect? Binomial Testing

In Germany a referee supported the use of the free kick spray introduced on the World Cup 2014. He reported some statistics. His data supported the assumption using the spray leads to more goals after ...
0
votes
1answer
21 views

How do you conduct regression analysis using SPSS when there is more than one dependent variable?

How do you conduct a regression analysis in SPSS using 1 predictor variable (personality score) and 8 dependent variables (stigma scores to 8 different case studies)? I have tried to use this process ...
0
votes
0answers
6 views

Why will higher order of polynomials using poly() function solve in lme model and lower orders won't?

I am modeling repeated blood pressure data over 24-h (300 patients, 13,000 observations) and have fit the following model with 9th order polynomial which has solved: ...
1
vote
0answers
18 views

Zero-intercept poisson regression model predicts better than a model with an intercept?

I have read some blogs/articles saying that intercept should not be suppressed. Recently, I used glmm.admb to model a ZIP (Zero-inflated Poisson) model which is giving better results without an ...
0
votes
0answers
20 views

Regression without intercept [duplicate]

I saw that here explain how to get the formula for getting a regression without intercept but I already know it (for example in R you get it outomatic with ...
1
vote
0answers
22 views

The econometrics of a Bayesian approach to event study methodology

Event studies are widespread in economics and finance to determine the effect of an event on a stock price, but they are almost always based on frequentist reasoning. An OLS regression -- over a ...
0
votes
0answers
12 views

How to find rows of a given matrix that satisfy a certain property? [migrated]

Suppose that I have a 90x4 matrix, say matrixgroup1, and some of rows are zero vectors. I want to find the rows that are not zero vectors. The code that I try was: ...
1
vote
1answer
12 views

Is this problem convex ? (regularization term on xTw)

Suppose we want to solve the following: $$ \min_{w} f(x^Tw, y) + \lambda g(x^Tw) $$ with $f$ a (logistic) loss and $g$ something like a variance. Is this a convex optimization problem ? What are ...
0
votes
0answers
25 views

How to check that the selected features are not overfitting

I'm trying to select best features for sentiment classification for a set of reviews, and using penalized SVM and Logistic regression to perform such task. by basically iterating over different ...
1
vote
1answer
113 views

Curious distribution

While checking my Android App Rating I saw this It's almost a quadratic progression! Is there any explanation for such a rating?
3
votes
1answer
39 views

Is stratified meta-analysis more or less objective than meta-regression?

Reviewer asked me why I use meta-regression as a way how to deal with heterogeneity among effect sizes instead of conducting stratified meta-analysis. I tried to google "stratified meta-analysis" and ...
1
vote
0answers
16 views

Maximum Entropy classifier, high precision but low recall

I'm working on a sentiment analysis study of twitter data using the Maximum Entropy classifier. I've gathered dozens of thousands of tweets. To produce features, I used unigram, bigram and dictionary. ...
1
vote
1answer
41 views

Hourly predictions using time series

I'd like to build a model based on time series. I have a dataset with records every 30 minutes for three months. What is the difference between modeling these data with the following kinds of ...
0
votes
1answer
22 views

Finding maximum likelihood estimates of parameters of multiple normal populations

I've just started studying maximum likelihood and likelihood ratio tests. I've calculated the maximum likelihood of a normal population with unknown mean and variance. However, I've been given this ...
1
vote
1answer
25 views

A reference for Pearson's chi-squared testing

I am wondering if there is a reference for the Pearson's chi-squared test suitable for technically-sophisticated audience that simply presents when the test (in its various forms) is appropriate and ...
0
votes
0answers
9 views

Add data series to highlight cases on a box plot (Excel, SPSS or R) [migrated]

first time user of this forum - guidance on how to provide enough information is very appreciated. I am trying to replicate the presentation of data used in the Medical education field. This will help ...
0
votes
0answers
11 views

Application of Inclusion-Exclusion Principle for circular arrangements

N people are invited to a dinner party and they are sitting on a round table. Each person is sitting on a chair there are exactly N chairs. So each person has exactly two neighboring chairs, one on ...

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