0
votes
0answers
2 views

When to use ANN with tensorflow?

I'm new to machine learning and tensorflow and I'm confused as to why (and when) to use the types of ANN (ie recurrent neural network) with tensorflow? I know RNN is good for sequences of data/time ...
0
votes
0answers
3 views

When to include or reject correlation term in two variable linear regression

I am studying a treatment that degrades device quality and performed an independent sample test on two batches that had different initial quality. I analyzed the data with a two variable linear ...
0
votes
0answers
2 views

If the fitted hazard ratio from a Cox model is approximately 1, does that mean the covariate is not significant?

Does a hazard ratio nearly 1 indicate that the covariate's effect on survival time is 0? If so would the corresponding p-value routinely indicate statistical insignificance? In other words, can a ...
0
votes
0answers
4 views

Setting specific values on the X axis when using ggplot

I am trying to plot a graph showing the number of events at the Olympics as a function of the year that a specific Olympic took place. My data frame is called ...
0
votes
0answers
5 views

Using nlsLM() for importance sampling for pricing european optoins

I am trying to implement a method for finding an optimal drift in pricing European options with importance sampling using this article. The article in pages 489-490 suggests to use Levenberg-...
0
votes
0answers
5 views

Negative probabilities - what are the two ordinary pgfs that correspond to the gf of a half-coin?

In Half of a Coin: Negative Probabilities, author considers pgf of a fair coin represented by random variable, $X = 1_H$: $$G_X(z) = E[z^X] = \sum_{x=0,1} z^xP(X=x) = (z^0)(1/2) + (z^1)(1/2) = \frac{...
0
votes
0answers
2 views

Design experiment to measure dependence of probability on a parameter

I have a physical system that can be modelled as following: there is a function $f:[0,1] \to [0,1]$ so that, given a parameter $\theta$, the physical system computes $p=f(\theta)$, samples $y$ from a ...
0
votes
0answers
8 views

What exactly does the default option for ```tt``` in ```coxph``` do?

Why are coefficients and p-values in the following models differ like so? ...
0
votes
0answers
11 views

Line versus exponential distribution

If the portion of particles in some matter decreases linearly with a function of heat, can we model it as an exponential distribution?
0
votes
0answers
2 views

Power analysis in structural equation models

I’m getting different estimates when estimating sample size for a structural equation model when I use different utilities online. How would you calculate the sample size a priori for such a model?
0
votes
1answer
3 views

Spearman Correlation from 'two-ways'

I have two data sets where I am comparing where an object in the first data set, ranks in the second data set and vice versa. This leads to the assumption that the data set being compared against is ...
0
votes
0answers
5 views

Combining Fixed Effects and Random Effects Confidence Intervals, Is this Possible?

I estimated a random slope,random intercept model and have estimates of the fixed-effects $\beta_i$ and the random effects $b_i$. I also have their associated standard errors $SE_{\beta_i}$ and $SE_{...
0
votes
1answer
17 views

Is Simpson's Paradox always an example of confounding?

Is Simpson's Paradox always an example of confounding? Or is it possible to have a Simpson's paradox effect without an extra variable lurking in the background?
1
vote
0answers
3 views

Is Random intercept by items “parasitic” on fixed effects tied to items?

I have the following model (simplifying to get to the point): Y1 ~ X1 + (1|subject) + (1|item) X1 is "confounded" with item, meaning each item takes on one and only one value of X1. I have been ...
0
votes
0answers
6 views

How to ascribe and defend statistical significance in linear regression. P-value interpretation and alternatives

I am studying a treatment that degrades device quality and performed an independent sample test on two batches that had different initial quality. I analyzed the data with a two variable linear ...
0
votes
0answers
5 views

Simulating an alternative local linear model

I want to simulate an $y_{t}$ time series like this: $\begin{equation} y_{t} = \mu_{t} + \epsilon_{t}; \mu_{t} = \mu_{t-1}^{1+v_{t}} + \eta_{t}; v_{t} = 0.7v_{t-1}+ \gamma_{t} \end{equation}$ The ...
0
votes
0answers
5 views

Specifying glmer response variable

Any idea about why the following model specifications should give different fits? Let's say we have the same data in the following two formats- head(data_long) ID correct condition itemID ...
0
votes
0answers
6 views

Sampling from $k$ urns until drawing at least $n$ marables from any of them

What distribution describes sampling with replacement from $k$ urns with probabilities $p_1,\dots,p_k$ (where $\sum_i p_1 = 1$) until drawing $n$ marbles from at least one of them? It's not negative ...
0
votes
0answers
13 views

How Many Random Choices Before They Have All Been Picked About The Same # Of Times?

Given a set of numbers 1 through X, how many times do I have to randomly pick a number before all of the numbers have been picked an equivalent (roughly) amount of times? For example: Given numbers 1-...
0
votes
0answers
10 views

PCA for questionnaire reduction

people! I'm new here and also with data analysis, but the site has been very usefull with I'm doing. I'd like to have some opinion regarding if I'm in the right way with my questionnaire reduction. I ...
0
votes
0answers
9 views

Comparison of correlation coefficients

I performed a Pearson's Correlation on two normally distributed variables and Spearman's on two other non-normal variables. All I want to know please, is right to compare the two r values e.g. 0.3 (...
0
votes
0answers
3 views

Forthe problem of Mulit Armed Bandit what is the difference between simple regret and PAC setting?

I don't understand the difference between Simpler egret and PAC setting for MAB. Is the budget constrained PAC equivalent to Simple Regret Setting ?
1
vote
0answers
9 views

Data type ontology naming: continuous

In one part of my API, I have an hierarchical ontology of data types declared: ...
0
votes
1answer
5 views

Determining confidence for individuals' performance

Apologies if this is ridiculously basic - I have searched the site but my vocabulary is probably too limited to be successful. I have a group of individuals performing a task with a boolean outcome - ...
0
votes
0answers
8 views

Can you use the Poisson GLM if there is an upper limit?

I'm analyzing social network data where roughly 10 groups of 100 people are split into different sized teams. (For example, there are 10 schools, but some of the schools have 5 "classrooms" while ...
0
votes
0answers
10 views

Does binary_regression module work in Stata 14? [on hold]

I'm planning to update to Stata 14 from Stata 9. I tried downloading the user written program binary_mediation to use in Stata 9 (as described here), but Stata 9 informed me that it's a Stata add-on. ...
0
votes
1answer
21 views

Is this an SARIMA(0,0,0)x(0,1,4)_12?

I found someone's quick-and-dirty forecast of a variable $x$: $$\hat{x}_t = x_{t-12} + \frac{1}{4}\Delta_{12}\left(x_{t-1} + x_{t-2} + x_{t-3} + x_{t-4} \right)$$ Can this be viewed as an "optimal" ...
0
votes
0answers
10 views

Determine if a time-dependent Cox model is appropriate

Before the description, here are my questions (1) Is the set-up of my time-dependent data correct? (2) Are the ways I run my Cox proportional hazard model with a time-dependent variable/ non time-...
0
votes
1answer
16 views

Basic Proability Doubt

I have a basic probability doubt. If I have 5 different vehicles backstage, out of which 3 random can be showcased to the public. What is the probability of each vehicle to get to showcase? Once a ...
1
vote
0answers
11 views

Expectation Value of Standard Deviation from “k” Closest Samples

The question that I'm am trying to answer is how to determine the expectation value of the standard deviation of 'k' closest samples to value 'A'. The standard deviation and mean of the underlying ...
0
votes
0answers
6 views

Correlations computed within subject vs collapsing across subjects

I have model predictions (x) that I want to test against subject ratings (y). There are 20 stimuli per subject and I have data from 30 subjects. What I did initially was to collapse all (x,y) pairs of ...
1
vote
0answers
10 views

How to model my data with linear mixed models for contrasts analysis

I have a dataset containing one dependent variable which is the concentration of antibiotic needed to kill a bacteria, which was measured for several different antibiotics for three different ...
-1
votes
0answers
8 views

Sample weights? [on hold]

Aim of study was to know the prevalence of disease. Using PPS sampling 30 clusters were selected. From each cluster 40 individuals were expected. Few clusters have less than 40 individuals while few ...
1
vote
0answers
9 views

visualization of two sets of confidence intervals in a scatterplot

I am seeking some general ideas on how to more effectively present two sets of confidence intervals in a scatterplot. There are a total of 10 point estimates and the associated 20 CIs, 10 on each ...
1
vote
0answers
12 views

U or Inverted U shaped relationship in count data models

Some scholars test for curvilinear (U or inverted U shaped) relationship in nonlinear models such as Poisson and negative binomial. Please clarify 1) Isn't the relationship between a predictor and a ...
0
votes
1answer
26 views

How to generate heteroskedastic data for linear regression analysis given Y

I have at m different points on a surface representing an organ n measures of a organ property for n subjects (such as wall thickness). These values have been stored in a matrix Y with m columns and ...
0
votes
0answers
6 views

Apply word embeddings to entire document, to get a feature vector

How do I use a word embedding to map a document to a feature vector, suitable for use with supervised learning? A word embedding maps each word $w$ to a vector $v \in \mathbb{R}^d$, where $d$ is some ...
0
votes
1answer
12 views

How to measure if data conforms to logarithmic curve

I am collecting data that should closely resembles a logarithmic curve. I have many datasets. How can I measure how closely each dataset resembles a logarithmic curve and call out any outlying ...
0
votes
0answers
8 views

How to model variability within timepoints when DV is a proportion per timepoint

(Edited question) I am looking at some quality improvement (clinical) data.... I have a dichotomous outcome over time - subjects either experienced or did not experience the event in question. I have ...
1
vote
1answer
15 views

Forecast (R) with Trend, Seasonality and Promotions (Causals)

I have aggregated sales data along with price discount at month level for two years. There are seasonality, trend and also causals - the impact of price promotions (discount, in percentage). I want to ...
1
vote
0answers
9 views

Is stagewise feature discovery an invalid approach?

Suppose we want to build a regression or classification model. However, the features (independent variables used) are not all ready at one time. This is very realistic in business, because the data ...
1
vote
0answers
9 views

Variable Importance's reliability when model accuracy is low

I am trying to predict the termination events for a company. I also want to rank the most important variables that lead to termination. I ran a decision tree model and have the following questions: ...
0
votes
0answers
9 views

What is the proper inter-rater reliability analysis for continuous count data?

I'm analyzing a study where participants needed to list as many plausible solutions to a given question. There are two raters who are counting the number of plausible solutions, what is the best way ...
0
votes
0answers
12 views

How to put nested random effects and crossed random effect together inside in a nlme model?

In my model I have few covariates. Also I want to include the random effects state, county and ...
0
votes
0answers
11 views

Classification modeling on data with several levels of grouping [on hold]

I need to create a classification model on data with several levels of grouping. The data looks like the below graphic. I have TV data where in for every house I have several TV devices, each TV ...
0
votes
0answers
5 views

Calculate relative standard error with binomial proportion?

If one has a rule that says, do not report an estimated mean if its relative standard error exceeds 30% as that estimate is considered "unstable,"[1] how does one deal with a binomial proportion? For ...
0
votes
1answer
9 views

Results of Softmax regression on MNIST dataset

I'm currently following this lesson: http://ufldl.stanford.edu/tutorial/supervised/SoftmaxRegression/ , and after I coded their equation I got: ...
0
votes
0answers
4 views

How to tune hyperparameters for LLE?

I'm running LLE using Scikit-Learn (with the LocallyLinearEmbedding class), but there are a few hyperparameters and I would like to use grid search with cross-...
5
votes
0answers
20 views

Am I introducing bias by assuming birthdate is middle of month?

I have a dataset containing dichotomous disease measures as well as some continuous anthropometric measures on a cohort of patients, and includes their month and year of birth as well as the exact ...
0
votes
0answers
27 views

Detecting straight line segment in a series

I would like to detect "last" straight line portion in a plot in "R". For example,in the image below, that section would be the one shown under the Red bubble. What package or method should I use ...

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