1
vote
0answers
10 views

How to write up and report a Bayesian analysis?

Bayesian Estimation Supersedes the t-Test for John K. Kruschke is one of the most important papers that I had read explaining how to run the Bayesian analysis and how to make the plots. But the most ...
0
votes
0answers
6 views

Standard error for multiple regression? [duplicate]

My understanding of the standard error of estimate for a simple linear regression as a function of the sum of squares over the number of observations, but how do we interpret the standard error for a ...
2
votes
0answers
6 views

asymptotic unbiasedness of weibull mle

It's known that the MLEs of the two-parameter Weibull distribution scale and shape parameters are not available in a closed form. It is, however, known that they do exist, are unique, and moreover, ...
0
votes
0answers
10 views

non-parametric tests with significant difference in sample sizes

I have outcomes from a biological expt., where we have measured DNA lengths that has been affected. For condition1, I have 11 observations (length of DNA) and for condition2 I have approx. 116000. I ...
1
vote
0answers
5 views

Quantifying Reliability of Qualitative Testing

If a visual grading system is implemented to calculate the correlation between exterior and interior conditions (i.g., good, medium, bad), and a sample is taken from a known population to test the ...
0
votes
0answers
7 views

Multiple Imputation and using Rubin's Rules on non-linear combination of estimates

When using multiple imputation, Rubin's rules can be used to pool the estimates. From my understanding though, the pooling should only be done on parameters that are asymptotically normal. What I ...
0
votes
0answers
9 views

Confidence intervals of proportions for clustered data

I am trying to compute the proportion of "yes"'s in data that is clustered (participants within cities). If I ignore the cities, I get very nice and narrow confidence intervals. If I compute the ...
0
votes
0answers
4 views

Statistical Test for Two-Alternative Forced Choice Task (2AFC)

I conducted a learning experiment and assessed whether participants learned with a two-alternative forced choice (2AFC) task consisting of 100 items (25 items of category 1, 25 of category 2, items of ...
0
votes
0answers
26 views

Is there a name or reference in a published journal/book for the following variance formula?

Variance can be combined as $v=\frac{1}{n-1}(\sum_{i = 1}^{numGroups}n_{i}(m_{i}-m)^2+ \sum_{i = 1}^{numGroups}(n_{i}-1)v_{i})$ where $v$ is the combined variance, $n$ is the total sample size, ...
0
votes
0answers
19 views

Bootstrapping probability of success: what is wrong with my method?

I have a dataset where each row represents the outcome of individual bets placed by a population of players; each row has two fields: a player identifier and the outcome of the bet (1 if the player ...
1
vote
0answers
13 views

how to determine outliers in sample affected by ascertainment bias

I don't know if this is a really silly question as I'm in no way a statistician and I don't know if this is something that's actually quite rudimentary... Thanks for reading in advance too it got kind ...
0
votes
0answers
8 views

What do I use to describe the difference between two groups in terms of found latent variables

I need to describe what the difference between two groups (patients and normal controls) consists of in terms of latent variables that I can describe within each group. For instance, given this PCA ...
1
vote
1answer
15 views

Multivariate hypergeometric distribution in R

Say I have a bag of colored marbles. This bag contains 30 marbles, 2 of which are red, 3 are green and the rest are blue. I am now randomly drawing 5 marbles out of this bag, without replacement. I ...
0
votes
0answers
13 views

Joint distribution of Indepedent RVs

Can anybody knows how to find joint CDF of $P(X_1^2<p_1,X_1Y_1<p_2,X_1Y_2<p_3,Y_1^2<p_4,Y_2^2<p_5) = ?$ where $X_i$ and $Y_i$ are independent zero mean Gaussian random variables. ...
0
votes
1answer
13 views

Algorithm for sampling points according to weights

In my current problem, I need to sample points in proportion to the weights assigned to them and an original probability density function. Unfortunately, the weights aren't known ahead of time and ...
0
votes
0answers
9 views

Comparison of two correlation matrix of same dimension in R [duplicate]

I have two correlation matrices(Pearson).For example, metrices of (3 gene X 3 gene) for cancer samples and normal samples,individually. I have got gene-gene correlation for both sample. Now I want to ...
-1
votes
0answers
7 views

How to create a feature vector with scikit-learn? [on hold]

I have extracted some bigrams from a corpus, how can i create a feature vector with those bigrams with scikit-learn?, could anybody provide me some example?. Thanks
0
votes
0answers
9 views

tree - recursive partitioning

I am trying to understand recursive partitioning. I am simulating data. I am curious as to why, subsetting on var2, the coefficient estimates for var1 and var3 are becoming similar to those of the ...
1
vote
0answers
14 views

Is there a simple model that assumes a negative relationship between the mean and variance of response?

Poisson and Negative Binomial models assume that the variance of response is greater or equal to the mean of response. Is there a simple model where that assumption is reversed, i.e. variance goes ...
0
votes
0answers
7 views

Tendency tags based on series of numbers

I am trying to create tendency tags based on historic data. Ie, I have the following series always ordered in time: [w,x,y,z] where: ...
3
votes
0answers
9 views

TF-IDF Matrix and Regression

I am trying to build a regression model based on some tweets that my company put on our company feed. I would like to transform all of the tweets, and use them to tell me which word(s) were most ...
0
votes
0answers
12 views

Sum of two independent Weibull Random Variable

If $Y_0$ and $Y_1$ both have Weibull distribution i.e. $Y_0 \sim Weibull(\lambda_0,\beta_0)$ and $Y_1 \sim Weibull(\lambda_1,\beta_1)$ then what will be cumulative density function of $Y_0+Y_1$, i.e. ...
1
vote
0answers
24 views

What is relationship between Fisher Information and Variance in natural exponential Family?

I know that $Var(\hat\theta)\geq 1/I(\theta)$ where $I(\theta)$ is Fisher information. Let take an example of natural exponential family with density $f(x)=\lambda\exp(-\lambda x)$. In this case we ...
0
votes
0answers
10 views

Estimating proportions in a non-nested multilevel Bayesian model

Data: x: 1/0 successes (~ 800 data points) c: city code (1 to 78) t: "time of measurement", 1 (morning), 2 (afternoon), 3 (evening), 4 (night) The problem: I would like to estimate the ...
0
votes
1answer
15 views

Count the number of each unique row in a data frame? [on hold]

Suppose I have a data frame such like: ...
0
votes
0answers
6 views

Slow Lasso Performance Using sklearn

I am trying to use scikit-learn's LassoCV and/or ElasticNetCV functions to model a dataset with a large (>800) number of ...
0
votes
0answers
19 views

Number of possible statistical test can be used on the observation data.

I am working on research paper for diagnosis of cancer. List of Known prognostic factors Age of patient Size of tumor Grade of tumor Lymphnode involvement and list of Unknown factors which are ...
0
votes
0answers
14 views

Cross-correlation vs. Pearson Correlation

In general terms, what is the difference(s) between cross-correlation with lag = 0 and Pearson correlation?
2
votes
0answers
11 views

Instagram representative sample

I am doing a survey to study both sellers and consumers behaviour on Instagram in Kuwait. My question is how to decide on the sample size? What sampling design should I use since there is no sampling ...
0
votes
0answers
11 views

cross-validation to predict distribution of errors on finite test sets

In one use of k-fold cross-validation for evaluating classifiers, one trains k models, each on n(k-1)/k examples, and tests each on n/k examples. The average accuracy on those k test sets of size n/k ...
2
votes
0answers
17 views

LASSO prediction model question

I am trying to create a prediction model with 33 predictors (brain metabolite levels in various regions) and 8 observations (cognitive test scores) with p>>n problem using LASSO in MATLAB (...
0
votes
1answer
18 views

Systematic change of proposal density of metropolis algorithm - still a markov chain?

The problem is that I have a Gibbs-Sampler where one of the parameters has to be sampled via a Metropolis-Step from the respective FCD. I have problems finding a suitable scale for the Gaussian ...
3
votes
0answers
9 views

How to measure when error stabilizes (convergence) on Random Forests (or, when do I stop training)

I'm doing an implementation of Random Forests. As I was the original paper (page 11) and this nice book on the subject (15.3.1, page 592), they mention that when the out-of-bags error stabilizes (when ...
4
votes
1answer
60 views

Can we use leave one out mean and standard deviation to reveal the outliers?

Suppose I have normally distributed data. For each element of the data I want to check how many SDs it is away from the mean. There might be an outlier in the data (likely only one, but might be also ...
0
votes
0answers
27 views

Test for autocorrelation

I wanted to test if there's significant autocorrelation in my data. Here's the reproducible code(R!) and the result. It looks like that dwtest and bgtest and acf are all too much different. Can ...
2
votes
0answers
24 views

Variance of difference of $x_{i,t}$ and $x_{i,t+1}$

We have $n$ observations of human performance before and after a training program. We have a random sample of $n$ individuals and assume population distributions are normal. We thus have: $x_{1,t},\ ...
0
votes
0answers
19 views

How to calculate distribution of Y|X from distributions of X|Y and Y [duplicate]

I'm trying to solve the following homework problem: Let $X$ given $Y=y$ have a normal distribution with mean $y$ and variance one, and let the marginal distribution of $Y$ be normal with mean ...
2
votes
0answers
20 views

Solving non-linear equations in R with optimal inital values

I am using the rootSolve package in R to estimate parameters of non-linear equations. The basic formula is ...
1
vote
1answer
12 views

Three proportions testing null hypothesis

I have the following question. In a random sample of 250 people with low incomes, 155 are in favour of a new piece of legislation, while in random samples of 200 people with average incomes and 150 ...
3
votes
2answers
44 views

Estimator for $E[X]^2$

I'm trying to understand the theory of estimators. As I understand it now, if you have an r.v. $X$ and take $n$ i.i.d. samples then an estimator for $E[X^{2}]$ would be $\overline{X^{2}}$ since ...
-1
votes
0answers
24 views

Statistical significance to a population

I have a question in regards to statistically significant sample sizes to a population. I am working with data in excel and wanting to put the formula for this into the workbook as well but have run ...
1
vote
1answer
33 views

What is considered to be “good” classification rate?

Let's say I am trying to figure out whether two classes can be differentiated. My methods may not be perfect, but I would like to know whether my features "mean" anything that may possibly be added to ...
0
votes
0answers
23 views

SVM accuracy evaluation

Could you please answer some of my questiona regarding SVM-RFE (svm with recursive feature elimination). I am using SVM-RFE with linear kernel for the binary classification and feature selection ...
1
vote
0answers
17 views

Does the density of daily data impact forecast accuracy?

I know it might be trivial but does the density of daily values impact the forecast accuracy? For example, if a call center receives less than 50 calls for weekdays and less than 10 calls for weekend, ...
0
votes
0answers
22 views

Statistical nomenclature: what family does “head” and “tail” - in the sense of data runs belong

If I look at mean, variance, skew and kurtosis they are nth moments. If I look at percentiles, quartiles, and medians they are order statistics. Both work together to make a textbook summary. The ...
-2
votes
0answers
28 views

why cannot we find an arima model for the daily forecast of a dataset with more than 2 years of historical data?

I faced this problem a few times. I used TBATS to fit a model to the daily forecast of a variable and then wanted to include other regressors to my forecast. So I used auto.arima. all of my databases ...
0
votes
0answers
8 views

Select the cases from a data.frame that have been used in a GLMM [migrated]

I am trying to see differences in the feeding-rate of one bird species between big forest patches and small ones. I have several forest patches of both sizes, and three years of study. Some ...
1
vote
0answers
16 views

Regression Modeling with Upper and Lower Bounds on target distribution

I am trying to run a simple regression model between a couple of variables, one of which is bound between values of (.25 - .75). This will be my target variable. I understand the beta distribution can ...
0
votes
0answers
17 views

How to solve hat check problem using R? [on hold]

Suppose n people go to a fancy restaurant. Each person is wearing a hat and checks his/her hat at the door as he/she arrives. The hat-check attendant gets tipsy throughout the evening, forgetting ...
1
vote
1answer
43 views

Using MySQL or r, or both?

I have a large dataset and I want to do statistical analysis on certain subsets of the data. At the moment I see this as a two step procedure: Import data into a MySQL database and use the world ...

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