What is the best way to know the best selection method for our logistic regression model ?   Forward Selection Backward Elimination Step-wise Selection Full Model.   I am running logistic regression in SAS EG.   I have tried running each of them for the data that we have but for each method I get different results. Some of the factors are common but some are not. Basically, I just want to understand the logic behind selection of the method. So, Is there a way we can identify that for a specific data one method is better than the other based on the results that we get ? Please help.  Thanks
Suppose we have $n$ covariates $x_1, \dots, x_n$ and a binary outcome variable $y$. Some of these covariates are categorical with multiple levels. Others are continuous. How would you choose the "best" model? In other words, how do you choose which covariates to include in the model?  Would you model $y$ with each of the covariates individually using simple logistic regression and choose the ones with a significant association?
Does going outside of range or line of sight after casting a spell have any effect? I've bought a  to use with my EOS 200D and while I love the wide aperture, it appears to be quite difficult to achieve sharp focus on people's faces when shooting at f/1.8. I've tried both using Dual Pixel focus in Live View and using the center focusing point in the viewfinder, but it doesn't get me perfect results.  Is this simply a characteristic of cheap wide-aperture lenses? Or is it impossible to get sharp focus with a fully open aperture?  When I'm at at home using a tripod and focusing on a still subject I do get good focus (so it's not a camera or lens issue). But it's hard to do with people who are slightly moving between shots. Show that $G$ is cyclic Here is a problem from Herstein.     Let G be a finite abelian group so that the equation $x^n=e$ has at most $n$ solutions in $G$ for every positive integer $n$. Show that $G$ is cyclic.   I will have to basically show that there exists an element $g$ in $G$ having order $o(G)$.   I showed that such an element exists if $o(G)=p_1p_2...p_k$ where $p_i$ are primes. But I could not proceed if $o(G)=p_1^{a_1}p_2^{a_2}$. I feel that if I can prove this I will be able to extend. Division by $0$ I came up some definitions I have sort of difficulty to distinguish. In parentheses are my questions.   $\dfrac {x}{0}$ is Impossible (  If it's impossible it can't have neither infinite solutions or even one. Nevertheless, both $1.$ and $2.$ are divided by zero, but only $2. $ has infinite solutions so as $1.$ has none solution, how and why ?) $\dfrac {0}{0}$ is Undefined and has infinite solutions. (How come one be Undefined and yet has infinite solutions ?) $\dfrac {0}{x}$ and $x \ne 0$, it's okay for me, no problem, but if someone else wants to add something about it, feel free to do it. Natural Sounding Text to Speech? I am looking for some easy to install text to speech software for Ubuntu that sounds natural. I've installed Festival, Gespeaker, etc., but nothing sounds very natural. All very synthetic and hard to understand.  Any recommendations out there? Countinuity of the identity map between different topologies Do you use "a" or "an" before acronyms / initialisms? View history of commands run in terminal Is there a way to save all my typed terminal commands and view it like history in a log book? When trying to install CrossOver deb I get "Error: Dependency is not satisfiable libpng12-0" I need to amend my return but I already received check from IRS with my refund. Should I cash it out now or wait until I amend my return? I need to amend my return, but I have already received a check from IRS (they approved my return that I need to amend). Should I cash out this check and then amend my return, or should I dispose this check and wait for a check from an amended return? Convergence in measure and almost everywhere In a finite measure space, let $\{f_{n}\}$ be a sequence of measurable functions. Show that $f_{n}  \rightarrow f$ in measure if and only if every subsequence $\{f_{n_{k}}\}$ contains a subsequence $\{f_{n_{k_{j}}}\}$, that converges almost everywhere to f.   I can prove from converge in measure to converge almost everywhere, but I don't know how to write it down for the other direction. 'An avalanche of mail'? - it should be 'mails', shouldn't it? I came across this example on WordWeb while going through the meaning of the word ''.     the program brought an avalanche of mail (Just like "a group of man men").   I'm quite sure it should be mails. Kindly confirm. I recently upgraded a c# windows service to run as a 64 bit .net process. Normally, this would be trivial, but the system makes use of a 32-bit DLL written in C++. It is not an option to convert this DLL to 64 bit, so I wrapped the DLL in a separate 32 bit .net process and exposed a .net interface via remoting.  This is quite a reliable solution, but I would prefer to run the system as a single process. Is there any way I can load my 32 bit DLL into a 64 bit process and access it directly (perhaps through some sort of thunking layer)? Can prematurely powering down a computer cause bad sectors in a hard drive? Using 'very' with a noun Perfect infinitive What happens if there is a security problem in a package in the universe repository four years after the 12.04 LTS release; will the package be updated from upstream, patched, or left alone?  It's my understanding that the "5 years of support &amp; security updates" applies only to the core of Ubuntu -- anything in Main repository.  Not for things in the Universe repository.    For a more specific example -- if I install Ruby now, and want to use it for the next several years on 12.04 and it has a security vulnerability; while this might be patched in the upstream (so I could always download the latest from their website and compile it myself or use a PPA), will this upstream fix be migrated into the precise package repositories? What about backports? 99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people &amp; references I respect disagree.  Which of the following would you precede with "a" or "an," and why?   FAQ FUBAR SCUBA   [Note: I've read the questions  and , but the rules given there don't necessarily apply here.]    [Edited to add]  Here's a shorter (and hopefully clearer) version of the question…  In written English, which is correct (and why): "a FAQ" or "an FAQ"?  Some references with differing opinions:   an: the  and  a: the Microsoft Manual of Style for Tech Publications, 3e either: the  and How to change language of a specific application? Maximum log level exceeded in Developer Console Recently I have regularly been getting the error message below when opening the Developer Console:     The Developer Console didn't set the DEVELOPER_LOG trace flag on your   user. Having an active trace flag triggers debug logging. You have 316   MB of the maximum 250 MB of debug logs. Before you can edit trace   flags, delete some debug logs.   It happens in sandbox and scratch orgs. Haven't tried in production.  This only started happening recently. It goes away after clearing the logs but comes back after a few test runs.  Also: the Debug->Clear->Log Panel action is not working for me -- the logs stay put. I can remove them using the Query Editor as described , but it's pretty tedious.  Two questions:   Does anyone know a way to prevent the logs from exceeding the max level? Perhaps by having old logs cleared out automatically? Is there a known issue with the Clear Log Panel action? I am using Chrome btw.   Thanks!