Calculate sample size for linear regression
Simulating data to fit a mediation model
How do I create a key binding that allows me to mount my google drive? I want to mount/unmount my google drive using with a key binding without having to open a terminal. How can I set this up? I see lots of tutorials telling me how to root my phone (Motorola Droid), but none of them mention any potential "side effects."  Aside from a few relatively minor issues that seem to require rooting to fix, I'm basically happy with the phone and therefore a little leery of messing with a device that cost me a lot of money and is only a few months old.  Assuming that I'm just talking about rooting, and none of the typical post-root actions (like installing a custom ROM), am I taking any risks by choosing to root?   Does it have the potential to brick the device? Will it void my warranty? Will I stop getting updates? Will the cops show up at my front door the next day? (Yes, I'm being facetious.) Anything else I should be aware of?   (See also: ) I once saw watch a sci-fi movie or an episode of a tv series (not sure) in which:   Every police officer was a judge, and hence could act by themselves on the streets. Each "judge" had a gun, which appended their DNA to the bullet. This was used later in investigations about a crime scene, and I think was confidential before the trial was held. Only a judge could use the gun, try to use it and you've been electrified. Also the guns had a self-destruction feature. The main villain was an ex-judge who purchased and activated a very old "killer robot" which was a residue of a long-ended war. When a judge was exiled, they were given a copy of the book of law, and sent outside the city to enlighten the people outside cities.   Can you help me find it?  PS: It was difficult to select a title It seems that panel shadow is somehow hardcoded in KDE 4 and devs do not have any plans to change it and/or make it customizable. So, what I'm actually asking is some kind of hack (if there is any) which will remove the shadow of the panel in KDE 4.x completely (but without need to disable all desktop effects in the process).  Possible application: When a user wants a completely transparent panel, no top/bottom borders at all, the shadow is completely out of place and destroys the experience. I was working on a Beamer presentation, and noticed that, if I open a group scope and use a \tiny, the font size will bet set, but there will be a large space between lines. However, if I issue a \par at the end of the paragraph, it works as intended:  \documentclass[t]{beamer} \newcommand{\shortlipsum} {Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna. Donec vehicula augue euneque. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Mauris ut leo. Cras viverra}  \begin{document} \begin{frame} \shortlipsum  {\tiny \shortlipsum\par   % &lt;--- removing this \par will break line spacing } \end{frame} \end{document}   Here's a comparison between not using and using \par:    Am I doing it the right way? Why is \par the right way? su options - running command as another user I was wondering how to run a command as another user from a script.  I have the script's owner set as root. I also have the following command being run within the script to run the command as the hudson user:  su -c command hudson   Is this the correct syntax? What is the best way to remove accents (normalize) in a Python unicode string? Are the tags shown in a particular order? Loop-cut won't go all the way around When is it correct to use "yourself" and "myself" (versus "you" and "me")? I'm confused by why people use the following:     It's up to yourself.   Rather than:     It's up to you.   Another example of this would be:     Please feel free to contact ourselves if you have any problems.   Rather than:     Please feel free to contact us if you have any problems.   Are both of these correct?  Is there any reason for using the former? Explaining Horizontal Shifting and Scaling I always find myself wanting for a clear explanation (to a college algebra student) for the fact that horizontal transformations of graphs work in the opposite way that one might expect.  For example, $f(x+1)$ is a horizontal shift to the left (a shift toward the negative side of the $x$-axis), whereas a cursory glance would cause one to suspect that adding a positive amount should shift in the positive direction. Similarly, $f(2x)$ causes the graph to shrink horizontally, not expand.  I generally explain this by saying $x$ is getting a "head start". For example, suppose $f(x)$ has a root at $x = 5$. The graph of $f(x+1)$ is getting a unit for free, and so we only need $x = 4$ to get the same output before as before (i.e. a root). Thus, the root that used to be at $x=5$ is now at $x=4$, which is a shift to the left.  My explanation seems to help some students and mystify others. I was hoping someone else in the community had an enlightening way to explain these phenomena. Again, I emphasize that the purpose is to strengthen the student's intuition; a rigorous algebraic approach is not what I'm looking for. permission error when installing ttf-mscorefonts-installer/Can't drop privileges as file couldn't be accessed by user '_apt' What approach should I take to establish this logical proof? I need to design a logical math proof:  Write a detailed structured proof to prove that if m and n are integers, then either 4 divides mn or else 4 does not divide n.   Hint: Think about the form of the statement.   I was thinking about first proving that either 4 should divide m or n in order for the first part to be true, then use proof by cases to prove what happened when m was 4, and another case when n was 4...  But I got stuck, what do you recommend:    This is what I got so far: Claim: (m ∈ Z ∧ n ∈ Z) => (4 | mn ˅ 4 ∤ n)  Negated claim: (m ∈ z ∧ n ∈ z) ∧ ( P(n) ∧ ¬P(mn) )  Proof by contradiction  Assume m , n ∈ z:    Assume P(n) ∧ ¬P(mn):       Then ∃ q ∈ R, n = 4q       Let q0 be such that n = 4q0       Then mn = m(4q0)       Then mn = 4(mq0)       Then ∃ q ∈ R, mn = 4q        Then 4 | mn     Then P(n) ∧ P(mn) Then (m , n ∈ z) ∧ P(n) ∧ P(mn))    I know that is wrong, how can I fix it? Add a time limit before you can vote on a post For an infinite line charge, $E$ falls off with $1/r$; for an infinite sheet of charge it's independent of r! The infinitesimal contributions to $E$ fall off with $1/r^2$, so why doesn't the total $E$ fall off the same way for the infinite line and sheet charges? The Borel-Cantelli Lemma in  seems to be a sort of "corollary" of the .  It says:  "Let $(E_k)_{k=1}^{\infty}$ be a countable collection of measurable sets for which $\sum_{k=1}^{\infty} m(E_k) &lt; \infty$. Then almost all x $\epsilon \ \mathbb{R}$ belong to at most finitely many of the $E_k$'s"  I don't get three things:   "Then almost all x $\in \ \mathbb{R}$ belong to at most finitely many of the $E_k$'s"   What does that mean? Since the Borel-Cantelli Lemma comes after the "almost everywhere" definition, I guess: $\exists \ Z \ \subset \mathbb{R}$ s.t. $m(Z) = 0$ and $\forall x \ \in \ \mathbb{R} \setminus Z$, x belongs to $(E_{j}, E_{j+1}, E_{l}, ..., E_{m})$.   In the proof, one can see the $m(\limsup \ E_k) = 0$ part, stated as $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$. For some reason, $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$ implies that "Therefore almost all x $\in \ \mathbb{R}$ fail to belong to $\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]$ and therefore belong to at most finitely many $E_k$'s"   Okay, why? What is the contradiction if almost all $x \epsilon \ \mathbb{R}$ belong to all the $E_k$'s? Or a countably infinite subcollection?   What is the significance of this? Why not just state the Borel-Cantelli Lemma as "Let $(E_k)_{k=1}^{\infty}$ be a countable collection of measurable sets for which $\sum_{k=1}^{\infty} m(E_k) &lt; \infty$. $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$"? Create Generic method constraining T to an Enum I'm building a function to extend the Enum.Parse concept that  Allows a default value to be parsed in case that an Enum value is not found Is case insensitive  So I wrote the following: public static T GetEnumFromString&lt;T&gt;(string value, T defaultValue) where T : Enum {     if (string.IsNullOrEmpty(value)) return defaultValue;     foreach (T item in Enum.GetValues(typeof(T)))     {         if (item.ToString().ToLower().Equals(value.Trim().ToLower())) return item;     }     return defaultValue; }  I am getting a Error Constraint cannot be special class System.Enum. Fair enough, but is there a workaround to allow a Generic Enum, or am I going to have to mimic the Parse function and pass a type as an attribute, which forces the ugly boxing requirement to your code. EDIT All suggestions below have been greatly appreciated, thanks. Have settled on (I've left the loop to maintain case insensitivity - I am using this when parsing XML) public static class EnumUtils {     public static T ParseEnum&lt;T&gt;(string value, T defaultValue) where T : struct, IConvertible     {         if (!typeof(T).IsEnum) throw new ArgumentException(&quot;T must be an enumerated type&quot;);         if (string.IsNullOrEmpty(value)) return defaultValue;          foreach (T item in Enum.GetValues(typeof(T)))         {             if (item.ToString().ToLower().Equals(value.Trim().ToLower())) return item;         }         return defaultValue;     } }  EDIT: (16th Feb 2015) Christopher Currens has posted  below, which is well worth a look, and an upvote. I will remove this edit if the solution bubbles further up the page. EDIT 2: (13th Apr 2021) As this has now been addressed, and supported, since C# 7.3, I have changed the accepted answer, though full perusal of the top answers is worth it for academic, and historical, interest :) The impression that I got from the  films was that if  was successful, most of the world was going to suffer greatly. Basically everyone would serve Voldemort as slaves or die. So what's the point of serving someone who's probably going to ultimately end up betraying and/or enslaving you? I know the  hated , but is that really enough to justify tearing down Wizard society? Why exactly do the Death Eaters serve Lord Voldemort? Fear? Is the post-Voldemort world not that bad? (I for one welcome our ) I have seen somewhere that classical distances (like Euclidean distance) become weakly discriminant when we have multidimensional and sparse data. Why? Do you have an example of two sparse data vectors where the Euclidean distance does not perform well? In this case which similarity should we use? Field between the plates of a parallel plate capacitor using Gauss's Law