Shouldn't the usernames on a historically locked question update as well?
Old usernames stick to Community Wiki posts
Difference estimate & confidence intervals for $\chi^2$ test between 2 proportions I am using a chi-sq test between two proportions (). I am using this over the z-test for proportions because I do not think my data is normal.   My question is how do I get the difference (shift) estimate &amp; confidence intervals for this test.   For example,     Data1: 193/252=.77   Data2: 154/227=.68   P-value=.032 (I used the formula in the link above. I will also add my exact code below)  Shift Estimate: I assume its the difference between proportions, ie .77-.68=.09. Is this correct?   Confidence Interval: ??????????????????  Code for generating P-value (matlab):   % Pooled estimate of proportion  p0 = (n1+n2) / (N1+N2); % Expected counts under H0 (null hypothesis)  n10 = N1 * p0;  n20 = N2 * p0; % Chi-square test, by hand  observed = [n1 N1-n1 n2 N2-n2];  expected = [n10 N1-n10 n20 N2-n20];  chi2stat = sum((observed-expected).^2 ./ expected);  p = 1 - chi2cdf(chi2stat,1);  H=0; if(p&lt;.05), H=1; end I have seen many articles that talk about a star's "habitable zone" as the ring around it which is just the right temperature for planets to have liquid water, which is necessary for life. My question is, why does a planet need to have liquid water in order to sustain life? Who says that extraterrestrial life can't live off of some other kind of sustenance? align vs equation So basically, I'd like to use iwconfig to connect to my wifi network when I'm not inside X. But I just don't see a way to do it in the man page. Any idea? I am currently working my way through "A Concise Introduction to Pure Mathematics" by Martin Liebeck, and have been stuck on an excersise for a couple of days now. The question reads:  "Show that for an integer n $\geq2$, the period of the decimal expression for the rational number $\frac{1}{n}$ is at most $n-1$."  I've been trying to solve this without making any substantial progress. And yes, I have seen explanations that when performing a long division the decimal expression either terminates to $0$ or eventually repeats. But I haven't seen any proof of this that I've been satisfied with, even less do I know how to formalise this type of proof. I've tried to write out long division with arbitrary digits, but that obviously turns out to be too much of a hassle and basically impossible to draw any conclusions from. How to perform a logistic regression for more than 2 response classes in R I want to predict the impact of oil price over a Colombian oil company's stock price. I plan to use a logistic regression for this with a categorical variable (Up or Down given the direction of the stock price). Here is part of my dataset:  Minute  ecopet  profit  sum_profit   direccion  cl1_chg   sum_cl1    direccion_cl1 571     2160     0       10           Up         -0.03     0.00      Down 572     2160     0        0           Neutral     0.07    -0.03      Down 573     2160     0       -5           Down       -0.08     0.04      Up 574     2160     0       -5           Down       -0.07    -0.04      Down 575     2160     5       -5           Down       -0.08    -0.11      Down 576     2165     0       -25          Down        0.00    -0.19      Down 577     2165     0       -25          Down       -0.05    -0.19      Down 578     2165     0       -15          Down       -0.17    -0.24      Down 579     2165     5       -15          Down       -0.06    -0.41      Down 580     2170     0       -20          Down        0.03    -0.47      Down 581     2170    -10       0           Neutral     0.04    -0.44      Down   My dependent variable is 'direccion'. But as you can see it has 3 response classes. I know that to implement a binary logistic regression in R the code is:  glm.fit=glm(direccion~direccion_cl1, data=datos, family=binomial)   I am working with intraday information and plan to predict what happens when the oil moves up/ down (in the previous 10 minutes) and how it impacts the stock price in the next 10 minutes.  Could anyone tell me how could I perform this? I don't really know how to perform the logistic regression with 3 response classes. Thanks! The equivalence of sample correlation and R statistic for simple linear regression In the biblatex doc, it says ( Version 1.7, p.11):     thesis      A thesis written for an educational institution to satisfy the   requirements for a degree. Use the type field to specify the type of   thesis.      Required fields: author, title, type, institution, year/date      Optional fields: subtitle, titleaddon, language, note, location,   month, isbn, chapter, pages, pagetotal, addendum, pubstate, doi,   eprint, eprintclass, eprinttype, url, urldate   I would like to know if there is any "canonical" way to add the name of the supervisor(s) in a field of the .bib file (no .bbl manipulation please, I want my bibliography to be usable "as it" in several documents).  The expect result could be something like  :     Meand Myself. “A brilliant result, explained”. PhD thesis**, under the   joint supervision of Pr. Toto and Pr. Tata**. Université Paris 24,   Nov. 2013.   The "under the (joint) supervision" could be a string that would be declined in four ways:   under the supervision of  under the joint supervision of and the abridged forms Partitions of $n$ into distinct odd and even parts proof Let $p_\text{odd}(n)$ denote the number of partitions of $n$ into an odd number of parts, and let $p_\text{even}(n)$ denote the number of partitions of $n$ into an even number of parts.  How do I prove that    $|p_\text{even}(n) - p_\text{odd}(n)|$ is equal to the partitions of $n$ into distinct odd parts. Show that the number of partitions of $n$ for which no part appears exactly once is equal to the number of partitions of n for which every part is divisible by 2 or 3. Show that the number of partitions of $n$ for which no part appears more than twice is equal to the number of partitions of $n$ for which no part is divisible by 3. How to install HPLIP on my Ubuntu to support my HP printer and/or scanner? Let's assume that one has some HP printer and/or scanner and checked its support status on the corresponding page of HPLIP site - .  So one have the following information: the device Model name, Min. HPLIP Version and Driver Plug-in need.   What should one install to make Ubuntu fully support the HP printer and/or scanner? What resampling method is used in the raster 'Save as...' dialog? I received a raster that was resampled using the Save as dialog in QGIS. Now I need to describe the resampling process in a report. But I could not figure out the method used in the resampling. Is it Nearest Neighbor? Bicubic?  This question has been asked before () but the answer does not specify the method used.   I also tried looking at the QGis source code in GitHub, but unfortunately, I could not find where the magic takes place (I'm not a programmer) Did the date of Frodo's rescue out of the fire of Mordor have any particular meaning in The Lord of the Rings? Did the date of Frodo's rescue out of the fire of Mordor have any particular meaning in The Lord of the Rings?  We read in The Return of the King (Book 6 Chapter 4) that Gandalf states to Frodo and Sam:     The fourteenth of the New Year, or if you like, the eighth day of April in the Shire reckoning. But in Gondor the New Year will always now begin on the twenty-fifth of March when Sauron fell, and when you were brought out of the fire to the King.   Did Tolkien have any particular reason for choosing this date for Sauron's fall and Frodo's rescue out of the fire of Mordor, either allegorically or otherwise?  We are aware that Tolkien was not a fan of , but preferred the term applicability instead. Can linear momentum be conserved before and after collision in the presence of an external force? I'm a physics tutor for 11th and 12th grade students. I taught my students that momentum is conserved only when the net external force on the system is zero. But in the books we are following, momentum was conserved in the following cases in spite of presence of an external force:   A body (mass m1) is dropped from a tower (height h) and another body (mass m2) is projected vertically upward with initial velocity u. Find the velocities just after collision. (Gravitational force is the external force) Two bodies projected towards each other on a rough table surface, with all required parameters given asked to find the velocities after collision. (frictional force is the external force) Body explodes in mid air. Momentum is conserved before and after explosion. (Again gravitational force is the external force)   I explained to my students in all these cases though an external force is present it has negligible effect. But I'm not satisfied with my answer.  EDIT: Thank you for the comments and answer. It is clear that contribution of external force to change in momentum is negligible. Can someone do the calculation of taking change in momentum into consideration and showing that it is negligible? Is it possible to nest a 'find -exec' within another 'find -exec'? Something like the following is what I what I'm after,  but my code doesn't work, no matter how I escape {} and + ;     find ./ -maxdepth 1 -type d -name '.*' -exec \     find {} -maxdepth 1 -type f -name '*.ini' -exec \         md5sum \{\} \\; \;   After seeing this ,  I found that the following code works, but it isn't nesting find as such, and I suspect there is a better way to do this particular job.       find ./ -maxdepth 1 -type d -name '.*' \ -exec bash -c 'for x; do     find "$x" -maxdepth 1 -type f -name "*.ini" \     -exec md5sum \{\} \;; \ done' _ {} \+   Is there some way to nest find -exec without the need to invoke  a shell (as above), with all its whacky quoteing and escape constraints?    Or can this be done directly in a single find command,  using a blend of its many parameters? How can a capacitive touch screen be triggered without human contact? I want to robotically touch an iPhone screen without any human intervention.   I've done some experiments but have not found a reliable solution. It seems even styluses that work through gloves still rely on the capacitive characteristics of the human body.    Carrot held by human works Carrot held in plastic clamp doesn't Pogo Stylus works held by human and held by human through clothes Stylus does not work held in plastic clamp.  Stylus works held in plastic clamp attached to human through clothes via jump lead. Stylus held in plastic clamp with jump lead dangling off seems to work most the time.   Is it possible to mimic the human element using capacitors and other components? What signal does the capacitive screen need to be triggered?  Thanks Strip whitespace from jsp output How can I strip out extra whitespace from jsp pages' output?  Is there a switch I can flip on my web.xml?  Is there a Tomcat specific setting? How to align content of a div to the bottom Why does change in speed of a wave make it refract? When a light wave enters a medium with a higher refractive index (e.g. from air to standard glass) and its speed decreases, why does that make it refract/bend?  I understand that wavelength decreases and frequency stays the same and therefore its speed decreases, but I can't find anywhere whatsoever why the speed decrease cause the wave to refract. So could someone please explain this? Finding the null space of symmetric matrix generated by outer product Let $p, q \in \mathbb{R}^n$ such that $\|p\| = \|q\| = 1$ and define $$A = pq^T + qp^T$$ Find the null space of $A$.    I am not having very much luck. I have managed to show that $p + q$ and $p - q$ are eigenvectors, but I can't seem to connect those two. I know that since $A$ is generated by an outer product, it is of rank one. That implies that the rank of the null space is $n - 1$, but I can't seem to get any further. Can anyone help? Natural Sort Order in C#