Questions tagged [computing]

For on-topic questions involving statistical computing. Please include also some statistical methods tag.

42 questions
23 views

Stable and efficient computation of binomial expectations

Suppose we want to compute the expected value of some function $f(X)$ where $X \sim \text{Bin}(n,\theta)$. Taking $\mathbf{f} = (f_0,...,f_n)$ to be the function values over all possible outcomes of ...
57 views

Find true negatives in a confusion matrix

I'm trying to find the True negative in a confusion matrix, I have computed successfully from scratch the precision and recall/sensibility, now i need to compute the accuracy and specificity. This is ...
40 views

Is it methodologically correct to, in some specific situations, merge related binary variables into one continuous?

I have 10 yes/no binary variables regarding different types of economic risks associated with running a startup. I have a database of around 100 different startup companies evaluated on each of those ...
365 views

Evaluating the hazard function when the CDF is close to 1?

I need to evaluate a hazard function $h(t;\theta) = \dfrac{f(t;\theta)}{1-F(t;\theta)}$, where $f$ and $F$ are a pdf and a cdf, respectively, at many values of $t$ (and for several values of the ...
21 views

What role(s) does Statistical Computing / Computational Statistics play in Clinical Trials?

I am going to pursue a PhD in Statistics, and the two fields that I am really interested are Statistical Computing / Computational Statistics and Clinical Trials (mainly because I like doing ...
24 views

Computational Optimization of Cross-Validation in Training Models

TL;DR: If I run a 5-fold cross-validation which assigns 1 fold per core when my CPU only has 4 cores, is the 5th as costly (with respect to computation time) as the first 4 folds? Context: I am ...
122 views

In a neural network, how are weights adjusted between the third to last and second to last layer of neurons?

I haven't been able to find much information that explains back propagation in simple terms. I would like to know what is happening (what is the algorithm) to be able to code one in java. I know that ...
41 views

Computing new variable of nominal and scale z scores variables

I'm analyzing a set of data where participants' reaction time and number of errors made during the task were measured. As there were two trials (where same data was measured) I was thinking I could ...
193 views

Why is a fully marginalized likelihood so much more difficult to computer than a partially marginalized posterior?

I have a question in terms of Bayesian computation. Let's contrast parameter estimation and model selection. When performing a Bayesian hypothesis test, this involves computing fully marginalized ...
22 views

Expected value of 3-repeated keys for a cuckoo hash table

I'm trying to solve a problem for my data structures class and am having problem computing the expectation for this scenario. I have wrote the question to be as independed from CS as possible I have ...
1k views

Difference between pROC and ROCR in compute time and accuracy

I've been calculating receiver operating characteristic (ROC) curves on very large datasets for my thesis. I tried to run these in the pROC R package but the ...
21 views

Summarizing results obtained in different scenarios by different methods

I have generated different scenarios which depends on certain parameters $x_1, \dots, x_k$. I have evaluated each scenario with different methods. Summarizing, I have a value $S(m,x_1, \dots, x_k)$ ...
133 views

Back-calculating the log-likelihood ratio statistic from a hazard ratio

I am wondering whether and how can I back-calculate the log-likelihood ratio statistic from a Cox proportional hazard analysis with 1 degree of freedom. For instance, if I have an hazard ratio (HR) ...
479 views