0
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0answers
4 views

R Question: Find a 95% confidence interval for mu

Given that X is a random normal variable with mean=10 and standard deviation=5, generate 500 samples, each of size n = 70, from the distribution of X. For each of the 500 samples, calculate the mean ...
0
votes
0answers
3 views

Data set distribution by state compared to US pop distribution by state

thanks in advance for your help. -I have a survey data set in which people reported which US State they are from. -I have the proportions of the entire data set comprised of people from each state, ...
0
votes
0answers
6 views

Propogation of error in a matrix inversion

I'm trying to find the deterministic error bounds for some parameters calculated through distance geometry. The equation can be simplified to the following form: $ \left[\begin{matrix} x_1 \\ x_2 \\ ...
0
votes
0answers
5 views

Generate images with convolutional networks

So constitutional networks are used for image classification. They extract features automaticaly learning to recognise edges and their non linear combinations. Then the features are fed to a ...
0
votes
0answers
8 views

What is the condition for $Var(\sqrt{n}(\hat\theta-\theta))\to V$ as $n\to \infty$ where $V$ is the asymptotic variance

What is the condition for $Var(\sqrt{n}(\hat\theta-\theta))\to V$ as $n\to \infty$, where $V$ is the asymptotic variance of $\sqrt{n}(\hat\theta-\theta)$. That is $\sqrt{n}(\hat\theta-\theta))\to^D ...
0
votes
2answers
16 views

one-way anova, one group has no variance

I have 20 genotypes for comparison (each has n >or= 5), however one group (control) has no variation (each sample = 100%). Can I apply one-way anova in this case. If not, what test would be better. ...
1
vote
0answers
19 views

What is shrinkage?

The word shrinkage gets thrown around a lot in certain circles. But what is shrinkage, there does not seem to be a clear definition. If I have a time series (or any collection of observations of some ...
0
votes
0answers
5 views

Non-Causal time-series filtering techniques for standard noise with unkown variance. (EM vs. weiner vs. kalman)

This is a quick question about filtering stored time-series data using kalman/weiner filtering techniques or expectation maximization. I'm just hoping to fix some confusion about questioning ...
1
vote
0answers
8 views

Is it invalid to adjust my independent variable based on a regression model fit?

I have a dataset and I want to visualize the relationship between Outcome and Variable1, after adjustment for ...
0
votes
0answers
6 views

R: Plotting GLM residuals vs. linear predictor or response variable?

When assessing a GLM fit, why is it customary to plot residuals against the linear predictor rather than the response variable? I noticed that plot(glm) defaults to ...
0
votes
0answers
5 views

Comparison of two measurement methods

all, hope to have your help on one question. For a group of subjects, we have two types of measurements. M1 measured each subject every 6 seconds for 15 minutes, non-invasivly. M2 only measured each ...
0
votes
0answers
14 views

making predictions with log-log regression model

Is it necessary to exponentiate the predicted values in a log-log regression model? For example my model is: $log(y) = log(x)$ $log(y) = -0.5141 + 0.5377log(x)$ if I wanted to make a prediction ...
0
votes
0answers
4 views

How to compute empirical copula?

Suppose U is a 4 dimensional data series (x1, x2, x3, x4) each with size n and F(x1), F(x2) and F(x3), F(x4) are marginal distribution functions of (x1, x2, x3, x4). How can we estimate the empirical ...
7
votes
2answers
67 views

Why does gap statistic for k-means suggest one cluster, even though there are obviously two of them?

I am using K-means to cluster my data and was looking for a way to suggest an "optimal" cluster number. Gap statistics seems to be a common way to find a good cluster number. For some reason it ...
0
votes
0answers
12 views

Correlation between continuous and binary variables

Is there a way to check for correlation between a continuous variable (year of graduation) and a binary variable (yes/no--took a specific course) with n=85, particularly using SPSS? Our hypothesis is ...
2
votes
0answers
9 views

Pitfalls in Fitting Nonlinear Models by Transforming to Linearity

Some nonlinear models can be transform to linear models. My understanding is that there might be one-to-one relationship between the estimates of nonlinear model and its linear model form but their ...
0
votes
1answer
47 views

How may I evaluate my self study of Machine Learning?

I am trying to learn Machine Learning on my own. To do this, I try to read from textbooks, good web-based materials like Stanford or Caltech. I try to work out my exercises, and try to discuss my ...
0
votes
0answers
4 views

Statistical test for comparing two response options in the same survey item

Is there a way to determine whether the proportion of respondents that endorse one response option of a question is different than the proportion of respondents that endorse another response option of ...
0
votes
0answers
7 views

Adapting clustering to partial clutering

This is a question primarily about re-appropriating existing clustering methods to work when only a fraction of datapoints are likely to originate from a cluster (as opposed to a global background ...
1
vote
0answers
19 views

Practical exercise to solve SVM and logistic regression

I have a simple task regarding SVM and logistic regression, even though I know the theory behind SVM and logistic regression I still have a problem to solve them. Exercise. We want to learn a ...
0
votes
1answer
10 views

What are the differences between filters learned in autoencoder and convolutional neural network?

In CNN, we will learn filters to produce feature map in convolutional layer. In Autoencoder, each layer's single hidden unit can be considered as filter. What the difference between the filters ...
4
votes
1answer
185 views

Machine learning classifiers

I have been trying to find a good summary for the usage of popular classifiers, kind of like rules of thumb for when to use which classifier. For example, if there are lots of features, if there are ...
0
votes
0answers
15 views

How to perform a regression with orthogonal polynomials (such as laguerre) in R? [on hold]

Using R software, I'm trying to perform a polynomial regression on E(Y|X1, X2, X3). In fact, E(Y|X1, X2, X3)must ne equal to a linear combination of polynomial with orthogonal basis (such as Laguerre ...
0
votes
0answers
7 views

Sample size and power calculations for a randomized controlled trial

I need help with the power calculations to determine the sample size of a randomized clinical trial. This is a relatively simple trial with two arms: an intervention arm and a control arm. Patients in ...
0
votes
1answer
24 views

One-way repeated measures ANOVA vs. two-way ANOVA

In a balanced repeated measures one-way ANOVA, we compare the true averages of a response variable across time points. Are the results about the time effects equivalent to those from a classic two-way ...
2
votes
1answer
12 views

Within-group sum of squares of cluster

I have a multivariate dataset for which I have only a table including the cross-wise Euclidean distances between all points and a list giving the assignment of each point to one of several clusters. ...
2
votes
1answer
36 views

Self Study: ML Parameter Estimates — do I need numerical maximization?

I have a particular PDF with two parameters, specified as: $$\alpha \beta e^{-\beta x}(1 - e^{-\beta x})^{\alpha - 1}, \alpha > 0, \beta > 0, x_i > 0$$ Given a random iid sample $(x_1, ...
0
votes
0answers
4 views

Using Bxp function in R with varwidth [migrated]

I am quite new to R programming and have been given the task of representing some data in a boxplot. We were only provided the five figure summary of the data, i.e the lowest value, lower ...
0
votes
0answers
6 views

R HoltWinters - Odd dip in predictions

So, I have this time series that tracks the daily number of applications to a graduate program. Each application period is 64 days - so for each period, you start at zero and it goes up until the ...
0
votes
0answers
7 views

Will the classification accuracy vary if we first classify based on a single variable and then use the rest?

Let's suppose I am doing classification and that I have 99 features and another feature that says if the person is male or female. I have two options viz to build one classifier using all the ...
0
votes
0answers
20 views

Lattice/R: How to draw seperate legends for every plot? [on hold]

I am creating a plot of my data the following: library(lattice) levelplot(dist_0+dist_1+dist_2+dist_3~alpha*beta,data=r ) The resulting plot looks like: The ...
0
votes
0answers
3 views

Coda for visualizing Stan trajectories [migrated]

I'm using Stan (specifically, rstan) with a Bayesian univariate linear regression $y = \beta_0 + \beta_1 x + \varepsilon$. And I'm trying to use the Coda package to visualize the resulting ...
1
vote
0answers
22 views

Recommendation for linear regression with least squares book

I watched several videos on linear regression, mainly from Khan Academy. As I have no background in statistics, I thought this was a good way to get an idea of the topic. However I'm currently writing ...
0
votes
1answer
16 views

Interpreting ACF and PACF Plot

My raw data consists of a 60-day time series with a downward trend. The data is weekly so the frequency is set to 7. I calculated the difference of the data which looks like this When I run ACF ...
1
vote
0answers
6 views

data dependent quantiles

Could you please explain, what does mean "data dependent quantiles" as mentioned in the following paragraphe: Quantiles appear intuitively appealing to epidemiologists as they can be thought of ...
1
vote
0answers
5 views

Confidence interpretation from false negative rate

For my research I'm using a tool called seeSUMO, which predicts sumoylation sites in a protein based on sequence features. When it reports your results, it gives you a level of confidence for each ...
0
votes
0answers
28 views

Is the sum of all elements of the residual matrix equal zero under OLS?

I have the following OLS model $$ y_i= α+βx_i+ε_i , i = 1,...,N $$ I want to prove that $$ \sum_{k=1}^N\sum_{j=1}^N e_je_k =0$$ I did the following $$ \sum_{k=1}^N (e_1+e_2+e_3+...+e_n) e_k ...
0
votes
0answers
5 views

Clustering time series with missing values

Here's the thing. I have some time-series that I would like to cluster, but they can have missing values. One approach that may be ad hoc is to use an algorithm like K-medoids, and to use similarity ...
2
votes
0answers
12 views

Hand-picked items in the training set, good idea?

The training, validation and test sets for the classification problem I'm working on were randomly sampled from real data. Because of this, I am fairly confident that there are representative. I want ...
1
vote
2answers
13 views

Cohen's d in non-significant results

I did several independend t-tests. Some of them are significant, some of them are not. Next, I computed Cohens $d$ for effect size. For significant results, Cohens $d$ feels intuitively reasonable ...
0
votes
0answers
14 views

choosing between non-linear/logistic regression models

We are fitting regression models to dose-reponse data obtained from drug assays. Where a drug has an effect on cell viability, there is often a sigmoidal relationship between the proportion of viable ...
1
vote
0answers
13 views

Data splitting in regression

Edit: The key point I'm attempting to understand is whether during a regression model building exercise, do I need separate datasets to: search for predictors and settle on a functional form ...
1
vote
1answer
34 views

Null Hypothesis with a Strict Inequality

On page 300 in Roussas' textbook "An Introduction to Probability and Statistical Inference" he states the null hypothesis for a test as $H_0: \theta>0.0625$ and the alternate hypothesis as $H_A: ...
2
votes
1answer
20 views

Simulated chi-square distribution doesn't match theoretical

Can someone explain why the distribution of Chi-square values I'm getting (using Pearson goodness-of-fit test) doesn't match the expected Chi-sqaure distribution? The test seems in this case to be ...
0
votes
0answers
12 views

Loopy Bayesian Networks for bidirectional data flows between nodes?

I have a Bayesian network where the information flows in both directions, i.e. both from parents and children to a specific node. I would like to have both those information flows included and get a ...
0
votes
0answers
7 views

What makes a good test set in an unbalanced corpus?

So, I have a machine learning classification problem, where the classes are quite unbalanced in the initial annotated dataset. My idea is to use Bootstrap method to help the classifier get new ...
0
votes
0answers
4 views

What is an intuitive explanation of Echo State Networks?

A reference can be found here: http://www.scholarpedia.org/article/Echo_state_network I am new to Recurrent Neural Networks(RNN) and still learning the concepts. I understand at an abstract level ...
0
votes
0answers
6 views

Correlation between balance of binary division and modularity in a social network

I'm working with social network data where the full network can be divided up into a ~30 subgroups of nodes based on existing organizational divisions. I'm interested in how integrated each of these ...
0
votes
0answers
13 views

Fitting a model while adjusting for some variable

I plan to figure out the effect of variable X on variable Y. I have time series data for both X and Y and a simple regression model should do the job. Unfortunately the variable Y is also affected by ...
1
vote
1answer
28 views

Searching for signal in a somewhat noisy landscape

I'm trying to implement a system to identify regions of high signal content in the presence of a noisy landscape. By high signal content, I simply mean intensity values significantly above background ...

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