1
vote
1answer
15 views

svd adds value before an elastic net model?

I learned that SVD eliminates redundancies. If you use an elastic net model, is it still greedy as stepwise models in general? or the fact that it has penalization factors reduces the greedy ...
0
votes
1answer
13 views

How do I apply MDS analysis on my data set?

Consider the following dataset (it is the emission probability matrix of a Hidden Markov Model): ...
0
votes
0answers
50 views

Probabilistic model Vs Weight based model

Can someone please explain what is the difference between probabilistic model vs weight based model with respect to ML context. When to use one over the other?
0
votes
0answers
20 views

Troubles reporting transformed variables for log and sqrt into a general equation

Good morning everybody, I see CrossValidated has really high level of questions and answer; I am just a student so I hope this question is not too basic... Suggestion of further readings available ...
4
votes
1answer
62 views

Free Throw Probability

I was asked this in an interview today. Would you rather try to make 2/3 free throws or 4/6? Why? I reasoned that if my chance of making an individual shot was > 2/3, I would go for 4/6 because it ...
0
votes
1answer
29 views

Multi Output Neural Networks

Up until know I only used neural networks to classify a single output, I set one output neuron for each class and check which neuron has the highest/lowest activation. What I am trying to do is to ...
1
vote
2answers
17 views

Expectation of squared non zero-mean data w.r.t. two distributions

I have the following model: $\hat{d}_i=a_i+b_i+c$, where $a_i$ is a zero-mean Gaussian r.v., $b_i$ is a r.v of unknown distribution, and $c$ is a constant. I want to estimate ...
0
votes
0answers
8 views

Understanding the variance to mean power function in Poisson gamma models

I have a biology background and try to understand what it means that the distribution of snps over the genome follows a Poisson gamma (PG) model. It is accepted that each chromosome contains Poisson ...
0
votes
0answers
13 views

Best way to graph probabilities of feature vectors

I have a lot of feature vectors in the form of: v1=[x0, x1, x2, x3, x4] where x0, x1, and x2 can take binary values. either 0 or 1 x3 and x4 can take values from 0 up to 9 I have a lot of vectors ...
3
votes
1answer
31 views

References and Best practices for setting seeds in pseudo-Random Number Generation

In this document, that concerns the "set seed" command, Stata people discuss issues related to the setting of seeds when generating pseudo-random numbers. A notable "don't" is "don't use serially ...
0
votes
0answers
26 views

Need help setting up multilevel logistic regression

I am trying to see the effect of a certain intervention in schools. The outcome variable is binary. We have students within schools. Also students' age is a covariate (doesn't changed before and after ...
2
votes
2answers
83 views

Which is correct way for regression line?

I have a set of data (some Frequencies per month, Var1 is the month): ...
1
vote
0answers
8 views

Approximating cox model with time varying covariates using poisson

How do you reformat a dataset in order to perform a cox regression with time-varying covariates as a poisson regression. I'm trying to run a survival analysis regression in python with time varying ...
1
vote
0answers
31 views

Minimum variance for sum of three random variables

I have been working on the following problem: Given you have VarX = 1, VarY = 4, and VarZ = 25, what is the minimum possible variance for the random variable W = X + Y + Z, or min Var(X+Y+Z)? My ...
0
votes
0answers
15 views

Survival using SPSS [on hold]

I have a database of about 50 subjects. Each subject received a number of implants (2-7 per patient). Therefore, there is one row per subject. I have a column for number of implants. I have another ...
0
votes
0answers
13 views

Help finding critical on a hypothesis contrast

I´ve tried finding the variance using the moment-generating function but apparently that is not the correct method for finding the critical. Can you help me with this?
0
votes
0answers
34 views

Could you please suggest a newbie about publishing Statistics related papers?

First of all pardon me if this is not the right place to ask something like this. If it is not the right place then I'll request you to let me know where I can discuss such things related to academia. ...
0
votes
0answers
14 views

Help in finding the joint distribution

There is a metric $H$ defined as = $\sum_{i=1, j \neq i}^{N} \min |u_i - u_j| * ..*|u_{i+d-1} - u_{j+d-1}|$ where $u$ is a multi dimensional vector of dimension $d$ and $u_i,u_j$ $\in \mathcal{R}^d$ ...
1
vote
1answer
42 views

How can I implement lasso in R using optim function

As you know lasso is a popular variable selection method of the form of $ (y-x\beta)'(y-X\beta)+\lambda \sum_i|\beta_i| $ the first is that it is possible to use optim() function in R to minimize ...
2
votes
0answers
32 views

Detecting a trend to increase, in a time series, in real time

Probably, someone who's into technical analysis of share prices eats stuff like this for breakfast. Me, I couldn't devise a theoretically acceptable approach. I have this thing (private working set, ...
2
votes
0answers
22 views

Expected numbers of distinct colors when drawing without replacement

Consider an urn containing $N$ balls of $P$ different colors, with $p_i$ being the proportion of balls of color $i$ among the $N$ balls ($\sum_i p_i = 1$). I draw $n \leq N$ balls from the urn without ...
0
votes
0answers
19 views

Adding predictor variables and/ or systematic judgement to time series forecasts

I have a ways to go with my forecasting general education --- but I'm doing a seasonal time-series forecast for predicting sales order volumes. It's mostly software sales, which does have a ...
0
votes
0answers
7 views

Determine accuracy distributions from measurements

Is it possible to determine the distribution of a certain measurement accuracy if one have a serie of measurements, carried out under fluctuating conditions, and the accuracy of the measurement ...
0
votes
0answers
15 views

What does the intercept correspond in the Anova() function in R?

I've been struggling to understand what the intercept sums of squares and p-value correspond to when I run a one-way ANOVA with Type "III" sums of squares using the Anova() function in the car ...
0
votes
0answers
8 views

Finding a hypothesis test based on the Neyman-Pearson about a parameter with a piecewise density function

I'm having trouble about how to start this problem. The density function for a random variable $X$ is: $$ f(x|\theta) = \begin{cases} \frac{1}{2(1+x-\theta)^2} & \text{$if x \ge \theta$} \\ ...
1
vote
0answers
28 views

t test for slope with binary variable

Cosider two random samples: one from the variable $Y_1$, with $n_1$ observations and the other one from the variable $Y_2$ with $n_2$ observations. Let $\mu_1$ and $\mu_2$ be the sample means of ...
1
vote
1answer
46 views

Interpreting a linear mixed effect model's interaction term

I am a biologist and am attempting to analyze the effects of time and location on depth. I was told I needed to use a mixed effects model to account for the random variables of Individual and tracking ...
0
votes
0answers
4 views

What is a good model for a regression analysis having TF-IDF dependent variable?

I am trying to build some models for a multivariate regression analysis that have as dependent variable TF-IDF values for some terms extracted from textual documents. An important characteristic of my ...
0
votes
1answer
23 views

Joint PDF of a set of equations

I am looking for a way to find the joint pdf of vector $Z=[Z_1,Z_2,Z_3,Z_4]$ where $Z_1= a_1 X_1^2 + a_2X_1Y_1+ a_3 X_1Y_2 + a_4Y_1^2 + a_5Y_2^2$ $Z_2= b_1 X_1^2 + b_2X_1Y_1+ b_3 X_1Y_2 + b_4Y_1^2 + ...
0
votes
0answers
13 views

What is the best way to do a seasonal ARMA (or ARIMA) in python?

Scikit learn and statsmodels don't seem to support this type of ARMA. I tried to use rpy2 python library, but that proved to be far too difficult to integrate, as my IDE was not able to recognize my ...
0
votes
0answers
14 views

using rate of change to find concavity of an oscillator [on hold]

I have an oscillator with a minimum and a maximum that plots curves smoothly (with very low noise) I would like to predict the next ten bars using the change it made from the previous bar to the next ...
1
vote
0answers
19 views

Fitting a model to data for prediction - best choice for data

I have some data I need to fit a model to that can be used for prediction (interpolation). The data is summarized by the plot below. The black line is x=y. I want to be able to fit a model so as I ...
5
votes
2answers
90 views

5 defectives rule of thumb

I have taught six sigma black belt classes using consultant sourced training materials which included the rule of thumb that when estimating the rate of occurrence of discrete events, like the ...
0
votes
0answers
8 views

How to properly renderDataTable in Shiny when theres is whitespace in the column headers [migrated]

I am rendering a DataTable from a data.frame to which I've given names like "Agent Name" for readability's sake. When I deply a shiny app to view this data as a DataTable, the whitespace in the column ...
1
vote
0answers
38 views

Bootstrapping a bootstrap

One of the criticisms of using a bootstrap procedure is that the results are not reproducible in the sense that you may come to a different conclusions when you re-run the bootstrap analysis again. ...
2
votes
0answers
37 views

Looking for and dealing with collinearity in a GLM

I've got this dataset with one continuous dependent variable and two categorical explanatory variables. I'm wanting to run glms on the data but I'm finding problems with what I think is collinearity. ...
0
votes
0answers
22 views

Maximum Liklehood estimator of Poisson

I am trying to solve the following problem, I was able to solve first three bits of the problem but after that i am stuck and do not have clue to solve the (iv) bit. The local government has ...
1
vote
2answers
38 views

Alternative for Fisher's exact test for count data in table bigger than 2x2

I have count data on different languages from comparable corpora. It looks something like this, where the counts give the number of clauses with that particular word order attested in each language ...
-1
votes
1answer
61 views

Probability that x samples from normal distribution sum to X

Lets assume that I have samples that fit to normal distribution. $f(x) = y$ How to calculate the probability that sum of values for $n$ next samples will equal $Z$. $\mathbb P(f(x1) +f (x2) + f(x3) ...
0
votes
1answer
10 views

Multivariate Regression on Multicollinear Categorical Variables

I am working on a dataset with a continuous response (which could be dichotomized), one continuous covariate, and multiple categorical variables. The continuous covariate (weight) is directly ...
0
votes
1answer
15 views

Test equality of two measurements for a outcome

I have a binary outcome which were measured with two methods say A and B such a $2\times 2$ table like this: ...
-1
votes
1answer
22 views

compute Expectation Propagation messages for sum

Can anyone help me in understanding how Expectation Propagation updates are computed when we have a function on several variables? Like this example: ...
0
votes
0answers
15 views

Early stopping methods for ANN applied to series prediction

Could anyone give advice or links to advice on early stopping methods for ANN trained with back prop applied to time series prediction? I know some methods for classification tasks but don't the ...
1
vote
1answer
27 views

Questions about non-standard test statistic for difference of two population proportions

Background I'm considering the number of observed 'successes' $x_1$ and $x_2$ from $n_1$ and $n_2$ independent trials respectively. These counts can be considered realisations of random variables ...
1
vote
1answer
35 views

Peak Hours for Tweeting

I am trying to figure out the peak hours during a 24 hour period for my companies twitter account. We are trying to find the sweet spot to optimize our interactions (RT+Replies+Favorites). I have ...
0
votes
0answers
23 views

Neural Network for hand written digit recognition

I have create the neural network with three layers. 1 layer - 500 inputs 2 layer - 500 inputs 3 layer - 10 output classes. I have synthesized the ...
0
votes
0answers
15 views

Which type of feature scaling to use [duplicate]

I've been writing some simple machine learning algorithms and looking at time-series data. In doing so, I have come across the use of feature scaling: rescaling and standardizing as they are referred ...
0
votes
1answer
20 views

How to cluster data with repeated measurements?

Most clustering algorithms assume that data points in each row are independent. I have some data with repeated measurements from individuals. I can use a standard algorithm, and then check to see if ...
0
votes
0answers
7 views

mixed design and simple main effect analysis in SPSS

Hope someone can help me. I have a within subject variable (Question, with 11 conditions) and a between subject variable (stimulation, with 3 conditions). I did an ANOVA and I obtained a main effect ...
1
vote
1answer
40 views

Solving a scrambled image puzzle with a genetic algorithm

I want to solve a puzzle such as this one: by using a genetic algorithm. When the number of pieces grow, and maybe some are rotated, the number of combinations become overwhelming. I am hoping that ...

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