2
votes
1answer
38 views

Kriging with individual errors

When evaluating a Kriging prediction, it is possible to include a hyperparameter $\lambda$ to account for noise in the data. $\lambda$ can be estimated as a parameter in a maximum likelihood ...
0
votes
0answers
8 views

Iteratively estimating multiple gaussians to data

I have a 2-dimensional data $D$ of locations per day (3 features: x&y coordinates and day) and I want to predict the areas of high probability values for the next day from the previous days. I ...
0
votes
0answers
3 views

Understanding changes in bookings per medical practice

I have data for counts of bookings per day. I have data for counts of active medical pracitces per day (active means that they have published appointments that are able to be booked in the past 28 ...
0
votes
0answers
2 views

SV in R: non-constant volatility for parameter estimation

I'm trying to estimate the parameters of a stochastic volatility model (see Zhang & Zhu, 2006) in R but instead of a constant volatility having a function (iv). This function can be estimated by ...
0
votes
2answers
19 views

In statistical terminology, what is the opposite of “peak”?

When we see a curve (or a normal distribution), we describe the highest value as "peak". Let's imagine we have a curve with only a minimum value (like an inverted hat), what do we call that minimum ...
0
votes
1answer
203 views

Machine learning with trinomial features

I have 100,000 students who have each answered some multiple choice questions. Given their performance I want to work out what the chances are of a particular student answering the next question ...
6
votes
2answers
3k views

Is it meaningful to calculate Pearson or Spearman correlation between two Boolean vectors?

There are two Boolean vectors, which contain 0 and 1 only. If I calculate the Pearson or Spearman correlation, are they meaningful or reasonable?
40
votes
7answers
64k views

Rules of thumb for minimum sample size for multiple regression

Within the context of a research proposal in the social sciences, I was asked the following question: I have always gone by 100 + m (where m is the number of predictors) when determining ...
0
votes
0answers
1 view

How to compare two spatial points patterns in R?

I have two spatial points data sets (relocations of animal A and distribution of plant B). How can I investigate if animal A is more likely to be where plant B is present? With the animal ...
0
votes
0answers
2 views

How to get database set for speech to lip movement

pls help me in finding human speech (Indian English)to lip movement mapping database or guide me about how to prepare it.
0
votes
0answers
10 views

K-fold cross validation dealing with an interaction term

I'm working on a logistic regression analysis and have a data set that contains ~12,000 data values (~6,000 values = 1; ~6,000 values = 0). I would like to use a k-fold cross validation process to ...
0
votes
1answer
121 views

how to impute missing values on numpy array created by train_test_split from pandas.DataFrame?

I'm working on the dataset with lots of NA values with sklearn and pandas.DataFrame. I implemented different imputation strategies for different columns of the dataFrame based column names. For ...
2
votes
1answer
104 views

Simulate t-tests of mean differences

I would like to simulate t-tests of mean differences. I would like to simulate data based on pre-specified (desired) mean difference between the variables and desired t value 3) and p-value ...
3
votes
1answer
43 views

Splines - basis functions - clarification

I have been reading the very helpful introduction on splines on http://freakonometrics.hypotheses.org/9184 and on http://www.stats.uwo.ca/faculty/braun/ss3859/chapters/splines/splines.pdf, as well as ...
2
votes
1answer
234 views

How to calculate cost matrix for cost sensitive meta classifier?

I have an imbalanced data set with 12 classes and want to use cost sensitive ensemble for classification, but I don't know how to calculate cost matrix for the classes. My question: what costs ...
0
votes
1answer
12 views

Which statistical analysis to use to compare the level of similarity between two large samples?

I'm writing a small speech recognition prototype as my side project, which matches pre-recorded words of the speaker. So now I'm thinking of comparing two sets of data (outcome of FFT) which are two ...
2
votes
1answer
148 views
0
votes
1answer
9 views

Single artificial neuron easily extendable to neural network

I'm working on implementation of artificial neuron which be extended to neural net. I want do implementation by myself to fully understand how it works. I start with perceptron with threshold ...
0
votes
0answers
17 views

Statistical technique to apply in Airline Industry

I am working to Airline Industry data where frequency of travelers in a year is up to 1. I need to increase the frequency of the travelers using some predictive modelling approach so that campaign ...
0
votes
0answers
10 views

RBF transformation on a Normally Distributed Random Variable

I have a random vector $\mathbf{X} \sim \mathcal{N}(\mathbf{m,\Sigma})$ which is transformed by a Gaussian Radial Basis Function into the random variable $\mathbf{Y} = K(\mathbf X) = \exp(-\lambda ...
2
votes
1answer
39 views

Appropriate reasons to exclude independent variables from regression

I am running a series of hierarchical regressions with a lot of independent variables. All the IVs show a loose theoretical relationship to the DV. My supervisor has suggested excluding IVs from ...
1
vote
2answers
119 views

How should I analyze a data set with 1 IV and 2DVs (all scale variables)?

Hello wonderful statisticians, I'm writing a proposal for a dissertation where I'd like to look at whether heart rate can predict 1) narrative coherence (as judged on a scale - but could also be ...
0
votes
1answer
28 views

Finding pattern from sparse matrix

I have a large sparse matrix which represents whether the action is happened or not. Each columns represent each action. Each row represents time. The data is collected for every 15min. Zero in the ...
0
votes
1answer
6 views

Finding a different pattern from the determined pattern

I have set the determined set of pattern that is like this (0.12,0.14,1.00,0.1,1.82), and I want to figure out whether 1000 other sets of 5 points follow the same pattern as the above (which is ...
0
votes
2answers
16 views

Grouping customers together into like groups based on multiple variables without a categorical variable

I am looking for a little guidance as to the correct approach to this problem. We have a list of IDs and roughly 8 different numerical variables such as quantity and revenue. Each ID is unique to the ...
1
vote
1answer
169 views

Using PyMC to obtain the posterior for the parameters of a parametric model?

I am a newbie with pyMC and I want to program an MCMC sampling for a complicated problem. I have a function given by in the following: $$g(r,c,\theta_1,\theta_2)=\frac{\delta_c}{\Sigma ...
0
votes
1answer
41 views

One-Sample Log-rank test statistic

Ok, I am totally confused, this is probably a pure math rather than a statistic question but please enlighten me. I found the logrank statistic formula being reported in the literature in 2 ways, but ...
0
votes
0answers
11 views

Multilevel logistic regression model

I have a dataset in which the DV is a binary choice outcome on a task trial. My IV's include binary stimulus property on the same task trial (e.g., stimulus is blue or red) as well as individual ...
2
votes
1answer
310 views

How to graph interaction effects for panel data

I have a pretty generic question which I am guessing could be relevant to many social scientists who deal with panel data sets. What are the best practices for making graphs about interaction effects. ...
2
votes
1answer
52 views
+50

Why is post treatment bias a bias and not just multicollinearity?

In this presentation by Gary King, he discusses post treatment bias as follows: Post treatment bias occurs: when controlling away for the consequences of treatment when causal ordering ...
2
votes
1answer
199 views

Gradient boosting algorithm (steps) question

So, far I have read following regarding boosting: Boosting is an ensemble technique. Train learner sequentially, where early learners fit simple models to the data. Analyze data for errors, that ...
0
votes
0answers
12 views

The relationship between adaboost and gradient boosting

I am reading the chapter 10 of "The Elements of Statistical Learning 2nd ed, (ESLII)", where the Adaboost algorithm is explained by minimizing the exponential loss using stagewise additive modelling ...
1
vote
1answer
16 views

Use CHIINV or CHISQ.INV to report Chi Square statistic?

I'm looking to report a chi-squared statistic for a chi-squared goodness of fit test using a 2x2 table. ...
1
vote
1answer
94 views

How to report data when there is interaction

I did a multivariable logistic regression analysis to estimate the effect of an exposure (E) on an outcome while adjusting for confounders. I investigated interaction and discovered a significant ...
1
vote
0answers
12 views

Test-retest correlation for panel data

I've run an experiment in which subjects rate how much they like six different objects on a 1-5 scale on two occasions. I'd like to obtain a summary measure of how consistent are the the subjects in ...
0
votes
0answers
8 views

A regression test like a glm, but measures the difference in betas

Like the title says, is there a regression test, similar to glm, that says whether a beta coefficient is (statistically) significant based on its difference from the Intercept? I'm currently doing a ...
4
votes
0answers
12 views

Information gain and mutual information: different or equal?

I'm very confused about the difference between Information gain and mutual information. to make it even more confusing is that I can find both sources defining them as identical and other which ...
2
votes
3answers
2k views

What is the difference between “limiting” and “stationary” distributions?

I'm doing a question on Markov chains and the last two parts say this: Does this Markov chain possess a limiting distribution. If your answer is "yes", find the limiting distribution. If your ...
0
votes
0answers
13 views

How to extract Type III Fixed effects under the glmer procedure?

I need to extract the Type III fixed effects for reporting in a manuscript but cannot figure out how to extract this information. My R code is as follows: ...
0
votes
1answer
24 views

Half-normal distribution and correlation?

In health sciences many variables may exhibit half-normal distribution. For example an inflammation process regarding one cell type or population in a tissue sample. The lack of the inflammatory cells ...
0
votes
0answers
15 views

Tennis Analytics: How to Build Model Predicting Player Service Point Win %

I have collected a large amount of tennis match data including player names, court surface, player ranking points at time of match, handedness of player, point by point breakdown of match etc. I ...
0
votes
1answer
9 views

Why CLMM function for ordinal mixed logistic regression changes the means?

I am using CLMM to run the ordinal mixed logistic regression model as the DV is ordinal number from 1 to 9 (rating scale). First I read the file and change the DV into ordinal using these commands: ...
2
votes
5answers
79 views

Why isn't independence checked standard in ANOVA?

The standard procedure for a one-way analysis of variance seems to be: fractile-diagram (or Q-Q plot) for checking normality Bartlet's test for heteroscedasticity But as standard I have never ...
0
votes
1answer
27 views

Is there a name for a graphical model where each node's probability depends on all of its ancestors, not just its parents?

I am interested to know if there is a name for a graphical model (specifically, a directed acyclic graph) where each node depends on all of its ancestors (as opposed to the typical Bayesian Net, for ...
0
votes
0answers
12 views

Random effects--mixed model

I have 2 study sites containing data from a species of wildlife. I am trying to evaluate resource selection use a use vs. availability analysis where used animal locations = 1 and random locations = ...
1
vote
0answers
12 views

Expectation of truncated normal X conditional on truncated normal Y

I am trying to derive: $E(X|a \leq Y \leq b)$ where $c \leq X \leq d $, $X$ and $Y$ are (doubly truncated) Gaussians with the same mean and different variance, and $a < c < d < b$ are the ...
1
vote
1answer
138 views

Significance of Difference between Two Extremes (Maxima/Minima)

I am comparing two different populations (with different sizes) of models, for each individual I have a score. I'd like to compare not only the difference of the two means but the maximum value. I've ...
0
votes
1answer
13 views

Iris dataset and a-priori probabilities

I have been playing around with two R packages for naive Bayes classification (e1071 and klaR) using the Iris dataset as an example. During the training phase, the outpur of the apriori probabilities ...
2
votes
2answers
41 views

What is calibration?

What does it mean to calibrate survey weights? Also, what are other definitions of calibration in statistics? I have heard it used in several contexts, particularly risk prediction (referring to ...
1
vote
1answer
117 views

Bivariate Kernel Density plot

Suppose that I have two variables, $X$ and $Y$ that I want to correlate, i.e. in the manner of a scatterplot of $(X_i,Y_i)$. But I also want to show the density of each variable. A scatterplot ...

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