Can we optimize regression problems that have categorical variables by encoding them if on the other hand we are inserting multicollinearity?
Why do we need to discard one dummy variable?
What is the word that describes the absence of bureaucracy? What is the word which describes the absence of formless, of long procedure with bureaucrats? I was thinking about formsless but it sounds weird... In grade school we learn to rationalize denominators of fractions when possible. We are taught that $\frac{\sqrt{2}}{2}$ is simpler than $\frac{1}{\sqrt{2}}$.  says that "there is a bias against roots in the denominator of a fraction". But such fractions are well-defined and I'm failing to see anything wrong with $\frac{1}{\sqrt{2}}$ - in fact, IMO it is simpler than $\frac{\sqrt{2}}{2}$ because 1 is simpler than 2 (or similarly, because the former can trivially be rewritten without a fraction).  So why does this bias against roots in the denominator exist and what is its justification? The only reason I can think of is that the bias is a relic of a time before the reals were understood well enough for mathematicians to be comfortable dividing by irrationals, but I have been unable to find a source to corroborate or contradict this guess. What should main() return in C and C++? What is the correct (most efficient) way to define the main() function in C and C++ — int main() or void main() — and why? And how about the arguments? If int main() then return 1 or return 0?  There are numerous duplicates of this question, including:       — For C++, with a very good answer indeed.     Related: Mouse Pointer Locator Due to a stroke, I have had some vision impairment in that I sometimes have a hard time locating my mouse pointer on the screen.  I have tried making the mouse pointer larger which helps but is still not the solution.  I am new to the Mac world and would appreciate your help.  In Windows, there is an option where pressing the CTRL key will help to identify the mouse pointer using a temporary display of several radiating concentric circles around the mouse pointer.  Is there something like this on OS X? Prove: If $a\mid m$ and $b\mid m$ and $\gcd(a,b)=1$ then $ab\mid m$ I use Windows 10 with the same Microsoft account on 3 different computers, each one with a different physical keyboard layout: ITA, UK, DE.  In "Control panel - Clock and International settings - Language" I have ITA as display language with ITA/DE/UK keyboard layouts, followed by ENG(US) with only UK layout.  In the same window I opened "Advanced settings" where I set an override (second drop-down list) to the default ("the first one on the list") language/keyboard: that would be ITA/ITA, while I want (on this computer) ITA/DE.  However, when now I log in in the other computers, I get ITA/DE there as well, while each computer should have a different one, being the physical keyboards different: ITA/DE here, ITA/UK on the second one and ITA/ITA on the third one.  If I change one, they all change. And if I don't apply the override, the issue seems to be the same.  Basically the last used language AND keyboard settings are stored on the cloud and applied wherever I log in.  How to set Windows 10 to remember, PER computer, the last used language/keyboard layout settings, without having that setting follow me? Is there software on Macintosh for adding GPS data to RAW files? How many outlets can you have on one 15 amp circuit? In my rebuilding project I have counted 18 outlets and lights on one bedroom circuit that travels through 3 rooms. Is that ok? How do you add a timed delay to a C++ program? I am trying to add a timed delay in a C++ program, and was wondering if anyone has any suggestions on what I can try or information I can look at?  I wish I had more details on how I am implementing this timed delay, but until I have more information on how to add a timed delay I am not sure on how I should even attempt to implement this. Reprojecting vector layer in QGIS? I have a series of layers of lines (shapefiles) in My Project. The CRS of some are different and to merge them they all must have same CRS.  When I use Processing/Toolbox/Qgis_algorithims/Reproject_layer the reprojection only works if it is allowed to save to temporary file somewhere (it will not change the CRS when I reproject if I try to save and replace it in My Project directory);   I must remove the original from the layer list and reproject the temp file (without changing the CRS) to get it into my project and name it appropriately.  Is there a better way to reproject a layer in Qgis? Changing ChildOf constraint influence to 0, but keeping the position it had as a child I had a sword object rigged with a single bone, with a ChildOf constraint making it a child of a sheath (with an influence of 1). Throughout an animation i move the sheath, and the sword bone follows as expected.  However, i cant seem to lower the influence of the sheath to zero and still have the sword retain the position it was just at, and I am wondering how i should go about making this happen.  Thanks for your time. What's the difference between \usepackage{ngerman} and \usepackage[ngerman]{babel} Creating label in QGIS? I am using QGIS 2.18.16 on Windows 10.    What I want is a label to appear within the boundaries of a polygon.    I select a layer, then select command Layer>Labelling, and I get:    From here, I can change "No Labels" to "Show labels for this layer".  But I can't actually create label text.  I find a clue in a prior question:    “Labelling polygon using QGIS?”    The answer was:  The layer you are trying to label must have at least one attribute field populated with data. You can then turn on labelling in Layer Properties and select which attribute field to use for your labels.  I can enter command Layer>Open Attribute Table, and what I get is:    If I need something in the attribute table in order to apply a label, how do I accomplish that? Nautilus bookmarks are missing since upgrade to 13.04 My bookmarks are not shown anymore after upgrading to 13.04 Raring ringtails and I can't add any new bookmarks. The function is not shown and the shortcut Ctrl+D isn't working either. Is this functionality just gone for some reason (as the split screen with F3) or is there something wrong with my upgrade?  Thanks for any hints. How do I study the "correlation" between a continuous variable and a categorical variable? Voldemort couldn't kill Harry as long as he called the Dursleys home. Why didn't he just murder the Dursleys? This would prevent Harry from being able to live there. I am using cURL to insert data into salesforce. It works with single record but I need to insert multiple records at a time. Is it possible to do so and is it possible via a REST interface? Given $\int_0^{\infty}e^{-x^2}dx = \frac{\sqrt{\pi}}{2}$, evaluate $\int_0^{\infty}e^{-a^2x^2-\frac{b^2}{x^2}}dx $ Given $$\int_0^{\infty}e^{-x^2}dx = \frac{\sqrt{\pi}}{2}$$ evaluate:   $$\int_0^{\infty}e^{-a^2x^2-\frac{b^2}{x^2}}dx. $$   I can find that  $$\left(ax+\frac{b}{x}\right)^2 = a^2x^2+2ab+\frac{b^2}{x^2}$$  therefore: $$\int_0^{\infty}e^{-a^2x^2-\frac{b^2}{x^2}}dx = e^{2ab}\int_0^{\infty}e^{-\left(ax+\frac{b}{x}\right)^2}dx$$  but I can't find any clue then. Honey changing into unusable, hardened clump How to change IP address to point to localhost?