As the question stated, is it possible for me to start applying graduate programs during forth year of undergraduate studies?
When applying to a PhD program in the US, how does the admissions process work? If an applicant is weak in a particular area, is it possible to offset that by being strong in a different area?  Note that this question originated from this . Please feel free to edit the question to improve it.
I asked  that turned out to have multiple correct answers. How do I pick between them to determine which to accept?  All of the answers were different. They were not the same answer given multiple times. Is there any difference between mapping and function? I wonder if there is any difference between mapping and a function. Somebody told me that the only difference is that mapping can be from any set to any set, but function must be from $\mathbb R$ to $\mathbb R$. But I am not ok with this answer. I need a simple way to explain the differences between mapping and function to a lay man together with some illustration (if possible).  Thanks for any help. Let users editing a question know if editing it would add it to the reopen queue This is sort of similar to , which was positively received, but was declined for technical reasons. I propose that users who are editing a post that was closed within the last five days be shown a notice on top of the edit form indicating that the post will be added to the reopen queue if edited, and that if one does not plan on editing the post into a state where it can be reopened, one should wait until five days after closure to make the edit. Closed questions are only added to the review queue once per closure by editing, and if a user comes by and makes a minor (yet benign) edit, the diff that reopen reviewers see is just that of the minor edit, and as such they dismiss the task as &quot;Leave Closed&quot;, which prevents it from being added to the queue again by another edit. This deprives the post author (and others interested in seeing the question reopened) of their chance to get the post reopened by editing. While some of these edits may be performed by users using (semi-)automated tools who would thus not see or overlook the warning, this will be a big help because 99%+ of users make edits solely manually and would thus see and possibly respond to such a notice. To help make this request more technically feasible, I propose that it instead only be loaded with the edit form, and that it should only be shown to users who can make binding edits. (Suggested edits occur at the time of approval, and the request to let the reviewers know has already been declined.) Here's an example of what I'm expecting:  This question was recently [closed/marked as duplicate]. This question will be added to a queue for possible reopening if you make this edit. If you are not planning to edit this post into a state where it can be reopened, please wait until [date and time after 70 days] to make your edit. If you are only making edits to the question's tags, please ignore this notice. How can I determine the name of the Bash script file inside the script itself?  Like if my script is in file runme.sh, then how would I make it to display "You are running runme.sh" message without hardcoding that? I'm positive that vs I strongly believe that In general, which one is conveys a stronger conviction/opinion? I did some quick google search but didn't find any interesting results.      I'm positive that   or     I strongly believe that Has the disputed flag message changed? I know how disputed flags work. Today, I reviewed a "not an answer" flag and marked it as invalid.   I've later seen a disputed message with this reason:     invalid flag         disputed - a moderator reviewed your flag, but found no evidence to   support it   Given that disputed flags are in the ,  Is this message applicable only to my flag or is this message also for the original flagger?  Or put otherwise, are all disputed flags now shown this message (or similar decline reason)?  I've run out of flags for today to test this further. Consider the following piece of Markdown code:  This is some regular text.      &gt;&gt;&gt; def factorial(n):     ...     return 1 if n &lt; 2 else n * factorial(n - 1)     ...   * This is a list item.      &gt;&gt;&gt; def factorial(n):     ...     return 1 if n &lt; 2 else n * factorial(n - 1)     ...    Notice that the second code block is preceded by a list item.   Why is the factorial code not properly formatted under these circumstances? To demonstrate the problem, I'll insert the Markdown code show above:    This is some regular text.  &gt;&gt;&gt; def factorial(n): ...     return 1 if n &lt; 2 else n * factorial(n - 1) ...     This is a list item                 def factorial(n):       ...     return 1 if n &lt; 2 else n * factorial(n - 1)       ...               This applies to numbered as well as unnumbered lists. This seems to be a basic issue, but I just realized that I actually don't know how to test equality of coefficients from two different regressions. Can anyone shed some light on this?   More formally, suppose I ran the following two regressions:  $$ y_1 = X_1\beta_1 + \epsilon_1 $$ and  $$ y_2 = X_2\beta_2 + \epsilon_2 $$ where $X_i$ refers to the design matrix of regression $i$, and $\beta_i$ to the vector of coefficients in regression $i$. Note that $X_1$ and $X_2$ are potentially very different, with different dimensions etc. I am interested in for instance whether or not $\hat\beta_{11} \neq \hat\beta_{21}$.   If these came from the same regression, this would be trivial. But since they come from different ones, I am not quite sure how to do it. Does anyone have an idea or can give me some pointers?   My problem in detail: My first intuition was to look at the confidence intervals, and if they overlap, then I would say they are essentially the same. This procedure does not come with the correct size of the test, though (i.e. each individual confidence interval has $\alpha=0.05$, say, but looking at them jointly will not have the same probability). My "second" intuition was to conduct a normal t-test. That is, take   $$ \frac{\beta_{11}-\beta_{21}}{sd(\beta_{11})} $$  where $\beta_{21}$ is taken as the value of my null hypothesis. This does not take into account the estimation uncertainty of $\beta_{21}$, though, and the answer may depend on the order of the regressions (which one I call 1 and 2).   My third idea was to do it as in a standard test for equality of two coefficients from the same regression, that is take  $$ \frac{\beta_{11}-\beta_{21}}{sd(\beta_{11}-\beta_{21})} $$   The complication arises due to the fact that both come from different regressions. Note that   $$ Var(\beta_{11}-\beta_{21}) = Var(\beta_{11}) + Var(\beta_{21}) -2 Cov(\beta_{11},\beta_{21}) $$ but since they are from different regressions, how would I get $Cov(\beta_{11},\beta_{21})$?  This led me to ask this question here. This must be a standard procedure / standard test, but I cound not find anything that was sufficiently similar to this problem. So, if anyone can point me to the correct procedure, I would be very grateful! I just synced my Mountain Lion Mail app with my Exchange work email account in order to have it locally on my machine (rather than continuously going through the web interface). However, now Mail fetches all the mails since the very beginning (which are a couple of years).  Is there a way (like on iOS devices) to tell Mail to only sync the last month or something configurable amount based on message count, download size or other similar restriction to prevent all messages from being stored locally? Recovering accidentally deleted files I accidentally deleted a file from my laptop. I'm using Fedora. Is it possible to recover the file? How can I uninstall a nvidia driver completely ? As expected, Nvidia drivers have reduced my customizations. I can't login to Unity 3D session. I can't find any content to help me to uninstall the driver and I don't know what to do as I have never uninstalled them before. Why is the top bar not changed on Stack Exchange, Area 51 and Ask Ubuntu? Assignment statement used in conditional operators Area51 proposals are being advertised now all over the network? I had an article, but I lost it.  It showed and described a couple of C/C++ tricks that people should be careful. One of them interested me but now that I am trying to replicate it I'm not being able to put it to compile.  The concept was that it is possible to change by accident the value of a const in C/C++  It was something like this:  const int a = 3;          // I promise I won't change a const int *ptr_to_a = &amp;a; // I still promise I won't change a int *ptr; ptr = ptr_to_a;  (*ptr) = 5;               // I'm a liar; a is now 5   I wanted to show this to a friend but now I'm missing a step.  Does anyone know what's missing for it to start compiling and working?  ATM I'm getting invalid conversion from 'const int*' to 'int*' but when I read the article I tried and it worked great. Why do we have no enzyme to digest cellulose? As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have an enzyme to digest cellulose? What training do doctors/Healers receive above their school education?   A fresh Hogwarts graduate does not seem to have all the skills required to be a Healer, so s/he would need to be learning those skills somehow/someplace. So how/where do they get those skills?  Also, there is one instance of a doctor being praised for inventing a healing spell. Is there any research system, like funding, trials etc or any other source of innovation? How many syllables are in the word 'hour'? Does the word 'hour' have 1 or 2 syllables? Recommended visualization libraries for standalone applications Print out elements from an array with a comma between elements except the last word