0
votes
0answers
2 views

Why is eta squared a biased measure of effect size in ANOVA? What unbiased alternatives can I use instead?

I encountered a weird effect when computing eta-squared in ANOVA. Here is a short simulation to demonstrate it. I simulate $k$ groups with $n=10$ each, with all values drawn from standard normal ...
1
vote
0answers
11 views

Is it okay to convert binary data to percentage data?

I have a within-groups study with 4 groups (400+ users). Each user answered 10 questions for each group. The answers were scored as right/wrong (1/0). Can the percentage correct for each user/group be ...
0
votes
0answers
10 views

Social Science Trade Book

I am looking for a book (not textbook) to use in an undergraduate statistics course. I would like to find a book with a clear central thesis relying largely on statistical reasoning and evidence to ...
0
votes
0answers
10 views

how to create a 95% confidence ellipse in R? [on hold]

I am trying to draw 95% confidence interval ellipses onto scatter plots of data. I have looked around and have seen various methods to do so, but I am an R novice, and so I don't understand where to ...
0
votes
0answers
6 views

Correlation parameter with small nonlinear sample like hour / day of week?

I have a dataset of magnitudes Y which gives the scale / magnitude of some event. Each event is also timestamped: Y = [(time1,mag1), (time2,mag2),...] I want to ...
0
votes
0answers
11 views

Degrees of freedom for a 3x2 mixed ANOVA

I want to report the results of a 3x2 (system x task) mixed ANOVA. System is a between-subject factor with 3 levels, while task is a within-subject factor with 2 levels. For one of the independent ...
0
votes
0answers
10 views

Research - Quantitative Data Analysis [on hold]

So I am doing research and I am lost. I have a questionnaire survey with all questions starting from Strongly Disagree, Disagree, Neutral, Agree and Strongly Agree. What can I do with the results? ...
1
vote
1answer
21 views

Expected value of the inverse of a random variable

Let $X$ be a random variable. $X$ can take the value 1 with probability $p$, and the value 2 with probability $1-p$. Can we write $E[\frac{1}{X}] = \frac{1}{E[X]}$? (note that $E[X] \neq 0$) Thank ...
0
votes
0answers
13 views

Random forest score in R

From sklearn import ensemble: clf = ensemble.RandomForestClassifier(n_estimators=150) clf.fit (X_train, y_train) clf.score (X_test, y_test) 0.83208955223880599 ...
0
votes
0answers
6 views

Using R : linear model (lm) - Fixed Effect Model - Vary intercept by different factor than the coefficient

I am having a problem setting up a panel data model (Fixed Effects) At the moment I am running the following code: ...
0
votes
1answer
14 views

Formula for regression coefficients for log-transformed predictors

A few years ago I came across a formula for computing the coefficients for a linear regression using log-transformed predictors, so that predictions made in the original (not log-transformed) ...
0
votes
0answers
16 views

Converting S-Plus Design package to R RMS package [migrated]

I am inheriting some code from S+ that fits a Cox Proportional Hazard model with imputed data. It then uses the Design package to get predicted values and confidence intervals. ...
0
votes
0answers
16 views

concept of p-vector and matrix

This might seem like a stupid question but I need some help. I have worked with vectors and matrices but the following paragraph from The Elements of Statistical Learning by Trevor Hastie et al is ...
1
vote
1answer
14 views

CFA chi-square value ordinal variables

For my thesis I need to know how the chi-square value is computed with a CFA for ordinal variables, using DWLS (preferably in R). I know that for continuous variables the chi-square is computed in the ...
0
votes
1answer
23 views

Predicting the increase/decrease of number

I have these entries in my database that looks like this: ...
1
vote
0answers
12 views

Can't reproduce results using foreach and RSNNS

I'm trying to train multiple Multi-Layer-Perceptrons using foreach and mlp(...) from the RSNNS package. As I ran into problems reproducing the results generated by mlp() and foreach in a parallel ...
0
votes
0answers
15 views

Is log transformation a proper way to reduce the weight of high vs. low values in logistic regression, and how do I diagnose when the DV is binary?

Consider the following case: I am analyzing a the effect of (among other variables) the age of a firm on a specific binary event. Theoretically my perception is that age matters, but not linearly. ...
-1
votes
0answers
7 views

Recommenderlab - Order evaluation results (list of lists?) [on hold]

I'm trying to evaluate the results of several recommendation methods from recommendationlab package, and get an ordered list(or data.frame ) by the MAE. I've tried several methods but none of them ...
1
vote
0answers
11 views

Whether a measure of efficacy or effectiveness is more appropriate for complex interventions

In terms of public policies aimed at health care sectors, effectiveness (i.e., performance in clinical practice) is deemed more important than efficacy (i.e., performance in laboratory studies), in ...
3
votes
1answer
18 views

Can we say a control / placebo group exists in a complex intervention?

In the case of something like acupuncture (as an example), it is very hard to set a placebo group or control group, since this therapy is not like taking drugs. Lets say if the needle is not in the ...
3
votes
1answer
20 views

Formula for dropping dice (non-brute force)

First of all I'm not sure where this question should be posted. I'm asking if a statistics problem is NP-Complete and if not to solve it programmatically. I'm posting it here because the statistics ...
5
votes
1answer
49 views

Is the converse of this statement true?

we know that: Ratios of scale functionals are location and scale invariant. My question is: is it true that every scale and location invariant functional can be rewritten as the ratio of two ...
0
votes
1answer
29 views

Question on AIC and BIC

What if the AIC/BIC is lower (negatively speaking) with the model including just the constant with respect to other ARMA versions? I don't think because k=1 it is lower by construction.
0
votes
0answers
8 views

Standard error for aggregated proportions

In order to obtain confidence intervals for proportions I'm trying to calculate the standard error, but I'm having difficulty working out what N should be in a case such as mine. My data is such that ...
1
vote
0answers
15 views

Correlation and coefficient with overlapping data

I have a time series data, with 5-period rates sampled at 1 period intervals. Essentially $$r_i = x_{i+5} - x_i ; ~~ i=1,...,N-5$$ This creates an overlapping data problem for regression. As far ...
8
votes
2answers
98 views

Interpretation of ridge regularization in regression

I have several questions regarding the ridge penalty in the least squares context: $$\beta_{ridge} = (\lambda I_D + X'X)^{-1}X'y$$ 1) The expression suggests that the covariance matrix of X is ...
0
votes
0answers
12 views

R - Lagged x-variables in ARIMAX [on hold]

I'm trying to fit a ARIMAX model in R on the form: $$y_{t}=a+b \times y_{t-1}+c \times y_{t-2}+d \times x_{t}+e \times x_{t-1}+error$$ Unfortunately it seems like you cannot lag variables in the ...
5
votes
2answers
159 views

Plotting distributions of variables across time

I have two datasets in the form of $q \times k$ matrices (variables $x$ and $y$). Both variables differ (lets assume that they differ by a constant). Columns of the matrices are subsequent points in ...
1
vote
0answers
14 views

Using deep learning for time series prediction with uncertain time series window size!

I'm new in area of deep learning and I am trying to use deep learning to do prediction on machine generated log data gathered as stream of data. I have seen LSTM an how it can be helpful to train ...
0
votes
1answer
18 views

Obtain adjusted means - Weight? Standardize? Use LSmeans?

I'm attempting to compare means from one year to another (and between groups at the same time point) by calculating adjusted values. I'm not sure what method to use. I've thought about the following: ...
0
votes
0answers
6 views

Mutual information for two soft clustering results?

I understand that mutual information (MI) of two distributions $X$ and $Y$ is defined as In the case of clustering analysis, say we are looking for two clusters out of 3 data points. We have two ...
0
votes
0answers
12 views

Scatterplot with edgeR DESeq Voom [on hold]

I am new in RNAseq and I started using edgeR, DESeq and Voom from Limma package to do differential analysis. I have a data frame of 30 couples of Normal and Tumoral tissues Since each method is ...
2
votes
0answers
13 views

Extension of Median to big data integer distributions?

I am analysing big samples of integer values. Because they come from a non-symmetrical distribution, I prefer to use the median to characterise central tendency, not the mean. However, due to the ...
0
votes
0answers
14 views

Forecasting a ARIMA(1,1,1) model

ARIMA(1,1,1) process with constant term $\mu$ is $X_t=\alpha X_{t-1}+\mu+Z_t+\beta Z_{t-1}$ where $Z_t$ is white noise with mean zero variance $\sigma ^2$. Find one step and two step ahead forecast ...
6
votes
1answer
77 views

Is there a known bias with telephone polls in the U.S.?

I was looking at a WashingtonTimes/ABC poll, and the results breakdown, especially by age, seemed surprising to me. So I went looking for bias. It said: "poll was conducted by telephone Dec. 11-14, ...
2
votes
1answer
59 views

Dimensionality reduction when number of samples is much larger than number of features

I was wondering what happens when the number of samples is much larger (e.g. $\times 200\:000$ times more) than the number of features? Is there any recommended way of reducing the samples' ...
2
votes
0answers
17 views

Diferrencing vs Moving Average

Moving Average and differencing a series can both be used to remove seasonality. Does the difference of these two lie in the model they are used? Moving Average used in classical decomposition and ...
6
votes
1answer
181 views

What is the problem with post-hoc testing?

My statistic professor says so, all the books that I look at state it: post-hoc-testing is unscientific. You must derive a hypothesis from theory first, and then collect data and analyse it. But I ...
3
votes
1answer
119 views

Why doesn't measurement error in the dependent variable bias the results?

When there is measurement error in the independent variable I have understood that the results will be biased against 0. When the dependent variable is measured with error they say it just affects the ...
3
votes
1answer
111 views

Definition of exponential family

I was reading these lecture notes and came accross the definition of GLM using exponential family of distribution. The latter seemed to have a bit of ambiguity, so I've checked that's it indeed the ...
0
votes
0answers
12 views

How to combine Gaussians in a two-dimensional data

I have two-dimensional data which can be summarized by a sample matrix M'(X,Y) , where each data point M'(x,y) consists of a set of numbers which I assume is generated by an underlying Gaussian ...
0
votes
0answers
9 views

Understand mixed models SPSS

On a mixed model on SPSS I got the following results: in the table called "Type III Tests of Fixed Effectsa" ...
2
votes
1answer
15 views

Confidence interval for polynomial linear regression

I have a model which is not linear but rather polynomial, and I have to estimate the parameters by giving a 95% confidence interval. There are plenty of formulas for regression of the type $Y = ...
0
votes
0answers
7 views

algorithms for color image edge enhancement using potential function

I want to use the method based on the use of weighting function also known as Parzen Kernels and form estimation of the probality density function (pdf) based on ...
0
votes
0answers
9 views

Omnibus test for several incidence rate ratios

Is there an omnibus test for comparing several incidence rate ratios, for example, irr1, irr2, irr3 with null hypothesis irr1=irr2=irr3 against alternative hypothesis irr1 ne irr2 ne irr3? Here are ...
1
vote
1answer
20 views

Interactions - using ratio of variables

I have 3 variables, colony size, colony age and growth rate (colony size/age). I am interested to predict various other properties ($y$) of a colony using these 3 variables; $y = a_1 \text{ size} + ...
0
votes
0answers
13 views

I have to know about the tslm function in r [on hold]

I need the full details of tslm function in r beacause I have to know this.Can you please give the explanation about the tslm when we use?,why we use?,how it works?
-1
votes
1answer
38 views

Correlation between two Likert items with a non-monotonic relationship

One of the assumptions for Spearman correlation is that there is a monotonic relationship between the two variables. I've created a scatterplot for two Likert item variables, but it seems impossible ...
0
votes
0answers
48 views

Determining demographics by restaurant visits

Assume Person X likes to visit different restaurants at different times. We would like to determine the current estimate of their demographic distribution based on all prior information we know from ...
1
vote
0answers
18 views

In R, generating every possible integral solution to a set of constraints [migrated]

In R, I’m trying to generate an array of all feasible integral solutions to a set of equality and inequality constraints. As an example consider the model: Model = a^2+b^2+c^2+d^2 Where: ...

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