Why is CFR calculated this way it is? Good afternoon everyone! I am only 17 years old, and this may sound like a stupid question...     First way   Anyway, we currently calculate the "case fatality rate" by dividing the number of patients who have died from a specific disease by the total number of those who got infected.      Second way   However, why don't we calculate the CFR by dividing the number of patients who died by the number of patients who had been successfully healed plus the ones who have died?       Explanation   I understand that maybe the data we have isn't enough nor accurate to use that reason once a country could have only 100 cases, which out of them, 70 died, and only 30 recovered - giving a false CFR having in count time.   Besides that, I also have read this article:  , in which they explained why the second way of calculating CFR approaches the first one.  But that isn't necessarily true. Let's take, for example, the case of COVID-19 in Italy. Because of the older population, the mortality rate is expected to be a lot higher in Italy than in China (about 7.2% compared to 2.1%). Nevertheless, the statistics have been constant for a long time, remaining at almost 45% of death ratio (if calculated using the second way). This doesn't make any sense, but it also looks more accurate than 7.2%. If we take on mind that only 10,950 people recovered from the 20,084 closed cases, the numbers seem right.    I also have in mind that the second way of calculating the CFR doesn't apply to all ages and genders once a 40% mortality rate can't be applied to people &lt;20 years the same way it is to people >60 years. The second way doesn't assume all of the population from a specific country. Although, neither does the first one. If we have to count the real consequences in a general way, isn't this the most appropriate way of calculating it?       Question   Why should we use the total number of cases (active cases + deaths + recoveries) to calculate CFR if the active cases didn't have an outcome yet?
Does COVID-19 have a case fatality rate of 41%? Is this formula correct? According to the data on the , as of 3rd February 2020 there were 17491 confirmed cases of COVID-19 globally, 536 total recoveries and 362 deaths. From my non-expert calculation this implies a mortality rate of:  (Nd / (Nd + Nr)) * 100 = 41%  where:  Nd is the total number of deaths, Nr is the total number of full recoveries.  This leaves 16593 people still suffering from the disease who have neither recovered or died.  This is in stark contrast to the publicly disseminated value of ~2% mortality, so have I made a mistake in my calculation or assumptions, or is COVID-19 much more dangerous than commonly claimed?    [After a helpful discussion in the comments, 'mortality rate' is not the correct term to use here, instead I should say ''.]
I have noticed that when I leave comments on a question and someone votes it up, I do not get a notification. If the upvote count would at least be more than 5, I would expect to be notified since that leads to a badge. As a(n) noun vs as only PHP errors NOT being displayed in the browser [Ubuntu 10.10] Will two-letter font style commands (\bf , \it , …) ever be resurrected in LaTeX? I understand that \bf and \it are now obsolete in LaTeX and that \textbf and \textit are proper, as they produce more sophisticated (in particular, cumulative and properly kerned) changes to font style. I have read the  and I understand the rules and their reasons, as well as the several other commands that are affected.  However, I find it convenient to use LaTeX for notetaking during lectures, and in that rushed environment, shortening a command by any number of keystrokes helps keep me from falling behind. \bf and its two-letter kin are still very useful to me for that reason, and once a presentation is finished I can go through and replace all appearances of \bf et al. with \textbf et al.  My question is this: is there a plan eventually to replace the short font style commands like \bf with the implementations of \textbf etc. some day, or should I expect \bf always to remain in existence but obsolete, for reasons of backward compatibility with original TeX? Original TeX has been greatly improved on in countless ways, but in the heat of transcription I sometimes miss its conciseness. How do I fix the left mouse opening the menu instead of breaking blocks? I have a 32GB iPhone 4 version 4.0.1. I have many photos on my phone, but I have deleted an important photo from my iPhone. How can I get this photo back from my iPhone? Is $D_n$, the dihedral group of order $2n$, isomorphic to a subgroup of $S_n$ ( symmetric group of $n$ letters) for all $n&gt;2$? Website Visible only to Registered users How can I speed up data transfer between local computers on a WiFi network? I have a router with ADSL Pentagram Cerberus 6331-42. Is it normal to have transfer speeds between two computers of max 1MB/s (not 1 Mbit)? How can I set my router up to make it faster at transferring data in my local WiFi network?  I have a PC and a laptop. Both are running Windows 7. I don't use a firewall. I've set the network area up correctly; I can see other computers.  Is it possible to make the router faster by changing its values? I don't use secure encryption such as WPA or WEP; only MAC filtering.  My values in Interface Setup > Wireless are:       Here are my thoughts after few years I've published this topic:    use 5Ghz bandwidth if possible  use range extender if Your router is too far  try wifi analyzer app for mobile phone to check what channel is the less used Let $A$ and $B$ be two matrices which can be multiplied. Then $$\operatorname{rank}(AB) \leq \operatorname{min}(\operatorname{rank}(A), \operatorname{rank}(B)).$$   I proved $\operatorname{rank}(AB) \leq \operatorname{rank}(B)$ by interpreting $AB$ as a composition of linear maps, observing that $\operatorname{ker}(B) \subseteq \operatorname{ker}(AB)$ and using the kernel-image dimension formula. This also provides, in my opinion, a nice interpretation: if non-stable, under subsequent compositions the kernel can only get bigger, and the image can only get smaller, in a sort of loss of information.  How do you manage $\operatorname{rank}(AB) \leq \operatorname{rank}(A)$? Is there a nice interpretation like the previous one? Book: Handful of children kept in a school as political mythological prisoners Attributes from an hstore-column as separate columns in a view? Let's assume we have a table where it has two columns, one an ID and one an hstore column, which stores key/value pairs.  You could query that column as such:  SELECT name, attributes-&gt;'device' as device FROM products WHERE attributes-&gt;'edition'= 'ebook'   Can you create a view for this table where the keys/values appear as columns in the view instead of all in the hstore column?  Example: I have an hstore key where it might have the key of amenity.  I want to create a view showing the the ID and the amenity values in a new view. Why are my photos not crisp? Trying to remember a short story (most likely from the sixties).  It starts with a soldier at the front line fighting an unknown enemy on the other side of the front line.  He then gets withdrawn and you realise that time is passing slower the further he moves from the front. He then spends years in peace away from the front, before being sent back to the front where only a short time (hours or days perhaps) have passed.      I seem to remember their was an inference that they were actually fighting against themselves, with their attacks coming back at themselves, which was perhaps the entire cause of the war, and an interesting critique on war.  I can't remember if this all this was stated explicitly, or just left for the reader to infer. Why would I open a low-rate 9 month CD instead of a higher rate savings account? One specific (popular online) bank is offering a 9 month 1.25% CD, while it's savings account is 1.90%.  There's no way I see interest rates tumbling in the next nine months, so why should I -- why should anyone -- get a 1.25% CD when savings accounts are paying 52% more interest?  (This question is not specific to this particular bank at this particular time.  It's about the general practice of buying low-rate CDs when savings accounts have a higher rate.) How do I check if an element is really visible with JavaScript? In JavaScript, how would you check if an element is actually visible?  I don't just mean checking the visibility and display attributes. I mean, checking that the element is not   visibility: hidden or display: none underneath another element scrolled off the edge of the screen   For technical reasons I can't include any scripts. I can however use  as it is on the page already. How to create a SQL Server function to "join" multiple rows from a subquery into a single delimited field? To illustrate, assume that I have two tables as follows:  VehicleID Name 1         Chuck 2         Larry  LocationID VehicleID City 1          1         New York 2          1         Seattle 3          1         Vancouver 4          2         Los Angeles 5          2         Houston   I want to write a query to return the following results:  VehicleID Name    Locations 1         Chuck   New York, Seattle, Vancouver 2         Larry   Los Angeles, Houston   I know that this can be done using server side cursors, ie:  DECLARE @VehicleID int DECLARE @VehicleName varchar(100) DECLARE @LocationCity varchar(100) DECLARE @Locations varchar(4000) DECLARE @Results TABLE (   VehicleID int   Name varchar(100)   Locations varchar(4000) )  DECLARE VehiclesCursor CURSOR FOR SELECT   [VehicleID] , [Name] FROM [Vehicles]  OPEN VehiclesCursor  FETCH NEXT FROM VehiclesCursor INTO   @VehicleID , @VehicleName WHILE @@FETCH_STATUS = 0 BEGIN    SET @Locations = ''    DECLARE LocationsCursor CURSOR FOR   SELECT     [City]   FROM [Locations]   WHERE [VehicleID] = @VehicleID    OPEN LocationsCursor    FETCH NEXT FROM LocationsCursor INTO     @LocationCity   WHILE @@FETCH_STATUS = 0   BEGIN     SET @Locations = @Locations + @LocationCity      FETCH NEXT FROM LocationsCursor INTO       @LocationCity   END   CLOSE LocationsCursor   DEALLOCATE LocationsCursor    INSERT INTO @Results (VehicleID, Name, Locations) SELECT @VehicleID, @Name, @Locations  END      CLOSE VehiclesCursor DEALLOCATE VehiclesCursor  SELECT * FROM @Results   However, as you can see, this requires a great deal of code.  What I would like is a generic function that would allow me to do something like this:  SELECT VehicleID      , Name      , JOIN(SELECT City FROM Locations WHERE VehicleID = Vehicles.VehicleID, ', ') AS Locations FROM Vehicles   Is this possible?  Or something similar? The origin of spin is some what a puzzle to me, everything spin from galaxies to planets to weather to electrons.  Where has all the angular momentum come from? Why is it so natural?  I was also thinking do photons spin? we always think of the wave as a standard 2d sin wave but could this rotate in 3d? What implications would this have?   And what about spacetime how does all the spinning effect?  This has always been avoided in all lectures and classes I ever went to. How do I simulate flip of biased coin? In unbiased coin flip H or T occurs 50% of times.  But I want to simulate coin which gives H  with probability 'p' and T with probability '(1-p)'.  something like this:  def flip(p):    '''this function return H with probability p'''    # do something    return result  &gt;&gt; [flip(0.8) for i in xrange(10)] [H,H,T,H,H,H,T,H,H,H] As you are all most likely aware already all domain registrars ask for your personal information.   Such personal information includes:   Forename and surname Address information Email address Telephone number   Personal information via WHOIS  Depending on the domain type such as  or  this information may become immediately available after the registration of the domain via a simple whois. If you do not want that (and in most cases you certainly don't) they offer a service where you can remove this information from the whois service but of course hiding your personal information adds yearly costs to the domain  purchase.  What happens if I use fake details when registering a domain?