Why do we create dummy variables?
Why do we need to dummy code categorical variables
In Windows there’re perhaps only a couple of important folders (by important I mean important in my logical picture of the Windows file system) in the installation drive (in my case C:\). Namely Program Files and Windows. I simply stay away from Windows folder and the “add remove program files” is good enough to handle the program files folder of Windows. Of course there’s a folder named Users where the users (who are not admins) can access only their folders.  Thus there’s a clear picture at some level in my mind of the Windows file system. In Ubuntu, when I reach the location /, there’s a huge list of folders, most of which I have no clue as to what they contain. The /bin folder seems to be the equivalent of the Windows folder in windows. The /usr folder seems like it’s the equivalent of the Users folder in Windows. But even the /home folder looks like it can fit the bill.  Please understand that I do understand, that Ubuntu (Linux) has a different character than that of Windows, i.e., there need not be exact equivalent of Windows functions, in Ubuntu. All I am looking for is a bit more clearer picture of the Ubuntu file system.   This question is a part of a bigger question which I am splitting up to make it more answerable. The original question can be found here: Yesterday, I have downloaded and installed Windows 8 Professional, after downloading it (legally) and burning it to a DVD, on my 3-year-old  (Intel Core Duo 2x2.4&nbsp;GHz, 4&nbsp;GB RAM,  hard disk drive).   The installation failed two or three times, each time differently (error codes, for example 0xc000021a, with an infinite boot loop), but finally I completely formatted the hard drive and installed. Seemingly, everything was OK.  However, after booting successfully, the OS is extremely slow. When I open the task manager, it shows that the HDD is at 100% - however, no application or background process or Windows process can be made responsible. I searched the Internet and found that Windows might try to "index" the hard drive, but I did't find a process that isn't also on my second computer, which still uses the Release Preview (restarting every two hours). Also, the startup is empty, and HD Tune and HDD Health show that the drive health is OK, even though I don't know how reliable these two programs are.  I looked for diagnose software from Toshiba, but they only offer tools for "Fujitsu branded Toshiba devices"; I tried it out, and it did not work on my hard drive.  Does this sound like a hard drive failure? The laptop is 3.5-years-old, has been carried around sometimes roughly and was used (and on) most of the time. However, it would have failed exactly the night before installing Windows&nbsp;8 Profesional, which seems - unlikely.  If this is a software error - then what did I do wrong if this occurs from the moment of installation (even the personalization at the end of installation took half an hour)? How can I fix this? I am looking for a word that describes both of these activities, however the word coding does not seem to be suitable.   Likewise with encryption and decryption, cryption does not work well. Solving "The ObjectContext instance has been disposed and can no longer be used for operations that require a connection" InvalidOperationException I need a step-by-step, simple and easy way to configure swappiness. How does \fontsize{}{} work? With the package anyfontsize I can use the command \fontsize{}{}. But the second argument seems to be without any effect. I read  that it is related to the line space. It doesn't work.  \documentclass{article} \usepackage{anyfontsize} \begin{document}  {\fontsize{1cm}{1cm}\selectfont First test : I need to put some text here.}  \bigskip  {\fontsize{1cm}{2cm}\selectfont Second test : I need to put some text here --- does it work?}  \end{document}     Any clue? What are the dangers of accepting gifts from unknown accounts on Steam? A user named 'steamfairy1' gifted me a game on Steam. I don't know this user, their profile shows no games, no friends and zero hours played. The profile of 'steamfairy1' was created the day I received the gift.  It very much looks like a scam, but I can't figure out how the scam is supposed to work. What's the worst thing that could happen if I accept the gift? Any idea what the trick here is? It could be just a random act of kindness and I'm just paranoid…  I contacted the Steam support, but they were unhelpful as usual: responding in the wrong language and with a canned one-liner that didn't make a whole lot of sense or had much to do with my question.  Keywords (not really tags, but I want this to be searchable): steamfairy, steam fairy Why does getopts only work the first time? Does the shebang determine the shell which runs the script? This may be a silly question, but I ask it still. If I have declared a shebang  #!/bin/bash    in the beginning of my_shell_script.sh, so do I always have to invoke this script using bash  [my@comp]$bash my_shell_script.sh   or can I use e.g.  [my@comp]$sh my_shell_script.sh   and my script determines the running shell using the shebang? Is it the same happening with ksh shell? I'm using AIX. To put it simple, there's a simple java swing app that consists of JFrame with some components in it. One of the components is a JPanel that is meant to be replaced by another JPanel on user action.  So, what's the correct way of doing such a thing? I've tried  panel = new CustomJPanelWithComponentsOnIt(); parentFrameJPanelBelongsTo.pack();   but this won't work. What would you suggest? I added a user to a group, but group permissions on files still have no effect What is serial voting and how does it affect me? I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause.  During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voting corrected".     What does this mean, and what caused it?  Did I do something wrong? Why did I lose all of that reputation? Is the system punishing me for leaving too many good answers?  Is there any way to earn it back? How to favorite a question from Android app? I've found an interesting question when browsing Freelancers.SE. I've tried to star (favorite) the question but I couldn't find the option...  How to star a question from the Android app? Currently my bibliography says "Literatur" (german). But I want something completely different there. How can I achieve that? Lightning tags in beta I came across some lightning tags that are still in beta, ex: lightning:input (Beta) lightning:tabset (Beta) etc  Not sure for how long they were in beta, is it advisable to use them for building UI and deploy to production? $a^m=b^m$ and $a^n=b^n$ imply $a=b$ Let $D$ be an integral domain and let $a^m=b^m$ and $a^n=b^n$ where $m$ and $n$ are relatively prime integers, $a,b \in D$.   How do I show $a=b$? What are some typical LuaTeX gotchas? Ward model implementation: specular component too weak I'm trying to implement the Ward shading model, the anisotropic, computationally efficient version:       This is how I made it:    float alphaX=0.5, alphaY=0.5; // asinotropic roughness float minFloat= 1.e-6;   vec4 Ward(vec3 L, vec3 N, vec3 V) {     vec3 H= normalize(L+V);     float NdotL= max(dot(N,L),0.0);     float NdotV= max(dot(N,V),0.0);      vec3 e= vec3(1.0,0.0,0.0);     vec3 T= normalize(cross(N,e));     vec3 B= normalize(cross(N,T));     float HdotT= max(dot(H,T),0.0);     float HdotB= max(dot(H,B),0.0);     float HdotN= max(dot(H,N),0.0);      float beta= -2.0 * ( pow(HdotN/alphaX, 2.0) + pow(HdotB/alphaY,2.0) ) / (1.0 + HdotN);     float den= max(minFloat, 4.0 * pi * alphaX * alphaY * sqrt(NdotL * NdotV) );     vec4 specular= Ps * 1.0/den * exp(beta);     return (Pd + specular) * NdotL; }   But I get a result similar to a lambertian surface or Oren-Nayar model, where the specular component is absent: Detect Chrome extension first run / update Two identical files; Apache says one is forbidden