Time complexity with for loop nested in while loop
Big O, how do you calculate/approximate it?
"Goose"–"geese" vs. "moose"–"moose" Why is it that the plural of goose is geese but the plural of moose is moose? The same goes for mouse and house. Mouse becomes mice, yet house becomes houses. I am currently developing a website which is going to take some time to finish. I need to move some 'stuff' to production frequently, while maintaining a under construction status. My front page will clearly mention that my website is under construction.  I know crawlers will access my URL before I am ready to go live. Should I tell them my site is under construction (no need to index)? If yes how?  P.S.: Eventually, I am ok to let them see my under construction front page. Let's say that I have a folder, within my Documents folder, that has files I want no one to access without a password.  Is there a way to lock down that folder so that it's password protected / encrypted?  In fact, is it possible to password-protect any individual folder? Log out button illogical placement In the previous version the logout button is under your username, which it can be found by clicking the down arrow. However, in the new version, after a couple minutes of searching, it is under the "site-switcher" button:        This is really illogical since the logout button is usually under your username, including Google and Yahoo! services.  I suggest bringing back the  which will definitely benefit new users and even old users. Where can I get flight info for a flight a month ago for an insurance claim? Flight stat sites will only show a weeks worth of data. I am having a strange problem in ArcGIS Toolbox.  I am trying to use the  tool from ArcToolbox. When I open the tool, there is no possibility to input Simplification Tolerance. Please see the attached image.  I can run the tool as a batch and from the Python window without any problem.  I am using ArcGIS 10(Editor) with Service Pack 5 on Windows 7 64Bit (English) and Windows Server 2008 64Bit (German). On both machines, I have the same problem. Any ideas?    I have reinstalled the software but the problem remains. How is stock price determined? Is stock price determined only by the last trade that takes place?  For example, if a stock I own is trading at $3.42, and I place a Sell Limit order for $0.00, will the stock price temporarily dip to $0.00?  Likewise, if I place a Buy Limit order for $100.00 for a stock that is trading at $1.23, will the price spike to $100.00?  Is there some sort of "average price" that is reported on the stock ticker?  Thanks for your help in understanding this! Wifi not working (Intel) on HP Spectre x360 13 (This question is only as reference, I will add the answer myself)  Suddenly the search in the expl3 documentation interface3.pdf no longer works. As an example searching for "divis" gives this as the first hit:    In sumatra there is no problem, other files (e.g. source3.pdf) works fine. What could be the reason?) I know this may be a tough or confusing question, but I have numerous existing materials I created and reuse for a project, which were all prepared for Blender Internal.  Now, I want to start the transition to Cycles, but I've hit a roadblock. How can I transition my materials without completely starting over? Or should I just forget it and start with fresh materials? At the beginning of  we see that Logan (a.k.a. Wolverine) and Colonel William Stryker were working together by the end of the Vietnam War.   For 5 years after the war, he lives in Canada with a girlfriend. But in  we see that Logan was part of some gang at the end of the Vietnam War.   My question is which of these are X-Men movie canon? Restore Unity Greeter I've installed XFCE Desktop environment, but when I decide to switch back to Unity, while uninstalling the XFCE packages, the LightDM keep starts like XFCE, and I want to restore the Unity one. I think that is called Unity Greeter. Can someone help me? This is somewhat of a beginner's question, but how does one interpret an exp(B) result of 6.012 in a multinomial logistic regression model?  1) is it 6.012-1.0 = 5.012 = 5012% increase in risk?  or  2) 6.012/(1+6.012) = 0.857 = 85.7% increase in risk?  In case both alternatives are incorrect, can someone please mention the correct way?  Ive searched many resources on the internet and I get to these two alternatives, and I am not entirely sure which one is correct. Start a longtable in Latex at top of next page I want to use the longtable environment for a table. However, I do not know how to place it at the top of the next page, as I can do with the table environment. Do you know how to do it? I wanted to align a set of equations to left. I found on the Internet that you can do it easily with align* environment.   I found it here:   So I did it:  \begin{align*}  f(b)-f(a)=&amp;f((b_1,b_2,\dots,b_k))-f((a_1,a_2,\dots,a_k))=\ &amp;=\sum_{i=1}^{k}[f((a_1,\dots,a_{i-1},b_i,\dots, b_k))-f((a_1,\dots,a_i,b_{i+1},\dots, b_k))  \end{align*}   Unfortunately, I got bunch of red errors saying that there are missing $s. Why? Doesn't that align* environment provide a math environment already? Let $G$ be a group and $\{H_i\}_{i\in I}$ a family of subgroups. I would like to find a condition that will imply that $\cup_{i\in I} H_i$ is a subgroup. I know that it's not true in general, I need help to find this condition.  Any help is welcome.  Thanks a lot. New question asking form sometimes leads to accidental double posts of questions I've noticed that with the new question asking form, sometimes, attempting to submit a question will post two identical copies of the same question.  I've  (), but at the time, I assumed it was just a temporary fluke. As far as I remember, I just reviewed the question, saw no errors, and submitted it. (That's all the info I have.)  However, I just saw this happen to someone else, so it can't just be a fluke on my end. , and . The author claims there that they did indeed double click the "Review" button, but their question didn't go through since it didn't have a required tag, but when they tried to submit the question with the required tag, they only clicked it once.  Also, now that I think about it, it could not have been just a temporary client-side issue on both our ends. The system is supposed to  if one tries to post more than one question in 30 seconds. Neither of us got a CAPTCHA. This means that the server accepted the double post, and so it's a server issue.  This has the effect of denying users badges that they would have otherwise qualified for, since a single negatively-received, closed, or deleted question . This means that even if the double post is deleted and the original is upvoted, the user won't qualify for that day since they've made a "bad" question on that day. (While they may be able to later reverse this 60 days later by undeleting and re-deleting their question - questions deleted more than 60 days later aren't considered "deleted" for the check - they often won't be able to, since most of the time, users will have downvoted the double post, which also disqualifies one from the badges.)  Can an employee go through server logs to see what happened in both these cases, and add some safeguards to prevent accidental double submissions of questions? This seems to have come up when the new asking form was deployed.  Update: There was another case just now:  was . As both have the exact same time of submission, this is an instance of this bug, since as I said above, this thing is ordinarily prevented by a CAPTCHA. Recovering broken or deleted NTFS partitions Choosing between $z$-test and $t$-test Background: I'm giving a presentation to colleagues at work on hypothesis testing, and understand most of it fine but there's one aspect that I'm tying myself up in knots trying to understand as well as explain it to others.  This is what I think I know (please correct if wrong!)   Statistics that would be normal if variance was known, follow a $t$-distribution if the variance is unknown CLT (Central Limit Theorem): The sampling distribution of the sample mean is approximately normal for sufficiently large $n$ (could be $30$, could be up to $300$ for highly skewed distributions) The $t$-distribution can be considered Normal for degrees of freedom $&gt; 30$   You use the $z$-test if:   Population normal and variance known (for any sample size) Population normal, variance unknown and $n&gt;30$ (due to CLT) Population binomial, $np&gt;10$, $nq&gt;10$   You use the $t$-test if:   Population normal, variance unknown and $n&lt;30$ No knowledge about population or variance and $n&lt;30$, but sample data looks normal / passes tests etc so population can be assumed normal   So I'm left with:    For samples $&gt;30$ and $&lt;\approx 300$(?), no knowledge about population and variance known / unknown.   So my questions are:   At what sample size can you assume (where no knowledge about population distribution or variance) that the sampling distribution of the mean is normal (i.e. CLT has kicked in) when the sampling distribution looks non-normal? I know that some distributions need $n&gt;300$, but some resources seem to say use the $z$-test whenever $n&gt;30$... For the cases I'm unsure about, I presume I look at the data for normality. Now, if the sample data does looks normal do I use the $z$-test (since assume population normal, and since $n&gt;30$)? What about where the sample data for cases I'm uncertain about don't look normal? Are there any circumstances where you'd still use a $t$-test or $z$-test or do you always look to transform / use non-parametric tests? I know that, due to CLT, at some value of $n$ the sampling distribution of the mean will approximate to normal but the sample data won't tell me what that value of $n$ is; the sample data could be non-normal whilst the sample mean follows a normal / $t$.  Are there cases where you'd be transforming / using a non-parametric test when in fact the sampling distribution of the mean was normal / $t$ but you couldn't tell? Understanding dummy (manual or automated) variable creation in GLM If a factor variable (e.g. gender with levels M and F) is used in the glm formula, dummy variable(s) are created, and can be found in the glm model summary along with their associated coefficients (e.g. genderM)  If, instead of relying on R to split up the factor in this way, the factor is encoded in a series of numeric 0/1 variables (e.g. genderM (1 for M, 0 for F), genderF (1 for F, 0 for M) and these variables are then used as numeric variables in the glm formula, would the coefficient result be any different?  Basically the question is: does R use a different coefficient calculation when working with factor variables versus numeric variables?  Follow-up question (possibly answered by the above): besides just the efficiency of letting R create dummy variables, is there any problem with re-coding factors as a series of numeric 0,1 variables and using those in the model instead?