Mohamed I. Riffi

12 Questions 57 Answers 0 Followers

Questions related from Mohamed I. Riffi

What are the most popular shrinkage methods?

Shrinkage methods are used in machine learning to select features and classify them. These methods are also referred to as methods of regularization regression. They include, ridge, lasso, and...

07 July 2019 2,937 2 View

In LASSO, do the selected features differ from one round of implementation to another?

LASSO ( Least Absolute Shrinkage and Selection Operator) is a regularization method used in logistic regression to select the related features of a high-dimensional gene expression data sets....

05 May 2019 2,473 3 View

Where can I find information about the k-out-of-n systems and their reliability?

Dear Colleagues, I am trying to use some results on m-spacings of the gamma (and exponential) distributions on the reliability of the k-out-of-n systems. I found a way to describe the life time...

01 January 2019 8,268 4 View

Is the use of mathematical axioms good or bad in mathematics? Is it difficult to prove axioms?

Some people consider mathematical axioms as points of strength of mathematics, other say that axioms are points of weakness. My question is why?! Is it so difficult to prove mathematical axioms?

12 December 2018 4,605 15 View

What are good subjects for master theses in the field of queueing models?

I am looking for recent subjects in the area of using Markov chains in queueing models or theory for the thesis of a master student in mathematics. Thanks a lot in advance. Mohamed I Riffi

02 February 2018 6,465 5 View

Where one can find fund for his/her mathematics research?

I wounder if any one can enlighten me on the possibility of getting support for a mathematics research I am working on. Thanks so much in advance for your help. Mohamed I. Riffi

12 December 2017 4,183 4 View

Do we really need to use the normal approximation to the binomial probabilities when testing statistical hypothesis?

Most of statistics textbooks approximate the binomial probabilities by the normal probabilities when testing binomial hypothesis especially when the sample size n is large enough. Now, since we...

10 October 2017 4,627 5 View

How to simulate a Markov Chain?

This Fall, I am teaching my master students an introductory course on Markov chains. I am looking for an easy/clear method to explain the theoretical basis of simulating a Markov chain; i.e.;...

10 October 2017 6,256 8 View

What would you do if you and your colleague agree to coauthor a paper and then he decides to write the paper alone and to publish it under his name?

What do you do when you and your colleague in RG agree to write a research paper and provide him with your ideas and some proofs and then he decided is to write the paper alone and to publish it...

07 July 2017 5,281 6 View

How can one describe the follwing conditional probability?

Suppose that an urn contains r red balls and w white balls. If n balls are removed from the urn without noticing their colors, then the probability, p, of drawing a red ball from the remaining...

06 June 2017 7,368 5 View

What's wrong with the computation of the probability that the exponential spacing Dn becomes less than t>0 for the first time?

Let X1, X2, ..., Xn be a random sample of size n for the standard exponential distribution and X1:n, X2:n, ..., Xi:n be the corresponding order statistics, where X1:n

05 May 2017 9,830 11 View

Distribution of gaps between prime numbers in a random sampe.

Dear Colleagues, Suppose that you have a random sample of size n from the set of positive integers. Some of the elements of this random sample will be prime numbers. Determine the positions of...

01 January 1970 8,078 8 View