Identify outliers using statistics methods Imagine this example. I've a field with following values:  10000 13455 90 12347 90 1111 235679   How can I identify that 90 are a outlier? Using average or standard deviation?  Thanks!
Detecting outliers using standard deviations Following my question , I am wondering if there are strong views for or against the use of standard deviation to detect outliers (e.g. any datapoint that is more than 2 standard deviation is an outlier).  I know this is dependent on the context of the study, for instance a data point, 48kg, will certainly be an outlier in a study of babies' weight but not in a study of adults' weight.  Outliers are the result of a number of factors such as data entry mistakes. In my case, these processes are robust.   I guess the question I am asking is: Is using standard deviation a sound method for detecting outliers?
A finite summation of double binomial coefficients I find the following identity and have checked on Mathematica, while I have no idea how to prove it:  $$\sum_{j=0}^n(-1)^{n-j}\binom{p+j}{j}\binom{n+\beta}{n-j}=\binom{p-\beta}{n}, \quad \beta&gt;-1, \quad p&gt;\beta-1.$$  It seems that proof by induction does not work and because of the gamma function, the transform technique does not work either. Adding the PHP json extension PostGIS nearest points with ST_Distance, kNN I need to obtain on each element on one table the closest point of another table. The first table contains traffic signs and the second one the Entrance Halls of the town. The thing is that I can't use ST_ClosestPoint function and I have to use ST_Distance function and get the min(ST_distance) record but I am quite stuck building the query.  CREATE TABLE traffic_signs (   id numeric(8,0) ),   "GEOMETRY" geometry,   CONSTRAINT traffic_signs_pkey PRIMARY KEY (id),   CONSTRAINT traffic_signs_id_key UNIQUE (id) ) WITH (   OIDS=TRUE );  CREATE TABLE entrance_halls (   id numeric(8,0) ),   "GEOMETRY" geometry,   CONSTRAINT entrance_halls_pkey PRIMARY KEY (id),   CONSTRAINT entrance_halls_id_key UNIQUE (id) ) WITH (   OIDS=TRUE );   I need to obtain the id of the closest entrnce_hall of every traffic_sign.  My query so far:  SELECT senal.id,port.id,ST_Distance(port."GEOMETRY",senal."GEOMETRY")  as dist     FROM traffic_signs As senal, entrance_halls As port        ORDER BY senal.id,port.id,ST_Distance(port."GEOMETRY",senal."GEOMETRY")   With this I am getting the distance from every traffic_sign to every entrance_hall. But how can I get only the minimun distance?  Regards, What does the caret (‘^’) mean in C++/CLI? How to detect if a mob has been hit in minecraft with command blocks? i am making a boss battle for my minecraft adventure map, and using a mob spawned with commands as the boss. When the mob gets hit, some command blocks will give the player a potion effect, but I can't figure out how to activate the command block when the mob gets hit. I am in the latest snapshot (16w03a). please help me (the person who answers my question will be given credit for it in my map) Rails lists have .first and .second – is there a .hundredth or .sixty_nineth ? Manifold that is NOT smooth Could someone provide an example of a manifold that is not smooth? All manifolds that come to mind are smooth! By a manifold, I mean a hausdorff, second countable locally euclidean space. Failed to Login : Invalid session (Try restarting your game) Minecraft Error Passing directly an array initializer to a method parameter doesn't work What leads to the existence of critical temperature? We know that $T_c$ is the temperature above which no amount of pressure could force a gas to liquefy. But why is this? Somehow I don't buy the point that the gas molecules exert too much pressure back to get close and turn into a liquid. If we had tens of thousands of atmosphere pressure (such as on the inside of hot planets), we should be able to liquefy any gas at any temperature. Permanent background ssh connection to create reverse tunnel: what is correct way? What *is* an Artificial Neural Network? As we delve into  literature, we get to identify other methods with neuromorphic topologies ("Neural-Network"-like architectures). And I'm not talking about the . Examples are given below.  Then, it makes me wonder: what is the definition of an artificial Neural Network? Its topology appears to cover everything.    Examples:  One of the first identifications we make is between PCA and a linear Autoencoder with tied-weights in the encoder and decoder and thresholded activations in the bottleneck layer.  Also, a common identification is done between linear models (logistic regression in special) and a Neural Network with no hidden layer and a single output layer. This identification opens several doors.  . ? ANN. Gaussian Process? ANN (with single hidden layer with infinite hidden units).  And so, just as easily, we can incorporate arbitrary regularized versions with specialized loss functions of these algorithms into a Neural Network framework.  But the more we dig, the more similarities appear. I just stumbled into , which makes the identification of a specific ANN architecture with decision trees, allowing these to be learned by ANN methods (such as Gradient Descent backpropagation). From this we can construct Random Forests and Gradient Boosted Decision Trees from solely Neural Network topologies.  If everything can be expressed as an Artificial Neural Network, what defines an Artificial Neural Network? Deep in my families history (1600's or there abouts) our family split in two. About three or four generations later two distant cousins got married creating a split / rejoin.                G.G.G.Parents A        +---------+---------------------------+     G.G.Grand Parent                      G.G.Grand Parent        |                                     |     G.Grand Parent                        G.Grand Parent        |                                     |     Grand Parent                          Grand Parent        |                                     | +------+-------+                     +-------+-------+ Aunt       Parent A - - -+- - - Parent B         Uncle                          |                   +------+------+                Child A        Child B                  ...           ...   So in this small example, the family splits in two at G.G.Grandparents and then rejoins later when Parent A and Parent B marry.  About 8 years ago I tried to find a software package which could model this and failed. Has anything happened in the intervening time?  Sorry I'm just asking in SE without doing much research, but I spent a lot of effort last time without any success and I am sure there is someone out there who can point me to an excellent package!    @ColeValleyGirl: I'm looking for a piece of software that is able to print out such a tree/DAG (thanks @ACProctor) in high enough quality to display/frame. All software I tried before didn't seem to be able to display this as they seemed to support mainly variations of Ancestors / Descendants rather than an output of all the people that had been inputed.  @AdrianB38: Essentially, I want to see "everyone". The tree I have was put together by my grandfather, who probably had a lot more data/people, but I've only got the hand written tree which highlights this split. It's essentially a tree of my grandparents ancestors (including this split which is joined at a common ancestor) and descendants (me + my family). I'd like to reproduce this in the computer (there is about 400 years - hundreds of people).  @AdrianB38: Re your point about generations, yes, I have that issue. I think it's only one generation, might be two - i've not looked at the tree in a while. The split between families happened over about 150-200 years iirc.  I can write an SVG generator if I really need to (I'm a Software Engineer) albeit I'm aware such a "loop"/"dependency" is painful to program for, but I was hoping that there was something which could handle this. How to limit execution time of a function call? What is the difference between sector and cluster? I have gone through wikipedia and other sites and here's the information I have obtained.  Sector: Smallest Addressable Unit (mostly 512 bytes) Cluster: Smallest Allocation Unit (equals to 1 or more sectors and the number of clusters depends on the file system).  Let's say in the below example:  sector =512 bytes and a cluster =8 sectors=4096 bytes. Now, I am having a hard time figuring out, when I am trying to create a file what does the file system do? Does it consider 4096 bytes as the smallest write/read unit or 512 bytes?  If the answer is 4096 bytes: When the manufacturer of the disk drives has provided 512 bytes as the smallest addressable unit, why does the file system consider cluster as the smallest unit? I mean, what are the advantages in doing so? OK guys I have this problem:  For $x,y,p,q&gt;0$ and $ \frac {1} {p} + \frac {1}{q}=1 $ prove that $ xy \leq\frac{x^p}{p} + \frac{y^q}{q}$  It says I should use Jensen's inequality, but I can't figure out how to apply it in this case. Any ideas about the solution? When to use a GAM vs GLM I realize this may be a potentially broad question, but I was wondering whether there are assumptions that indicate the use of a GAM (Generalized additive model) over a GLM (Generalized linear model)? Someone recently told me that GAMs should only be used when I assume the data structure to be &quot;additive&quot;, i.e. I expect additions of x to predict y. Another person pointed out that a GAM does a different type of regression analysis than a GLM, and that a GLM is preferred when linearity can be assumed. In the past I have been using a GAM for ecological data, e.g.:  continuous time-series when the data did not have a linear shape I had multiple x to predict my y that I thought to have some nonlinear interaction that I could visualize using &quot;surface plots&quot; together with a statistical test  I obviously don't have a great understanding of what a GAM does different than a GLM. I believe it's a valid statistical test, (and I see an increase in the use GAMs, at least in ecological journals), but I need to know better when its use is indicated over other regression analyses. Inspired by a , here's a list of the 'etymology' for the  hats. For pictures and a list of criteria, see  instead.  The list is a community wiki; feel free to edit it if you have more information about a hat. If you like to do some research, most hats have been featured in earlier editions, so you might be able to find more information in old Meta Stack Exchange questions. Use 'import module' or 'from module import'? The definition of "Lie group" typically restricts to a smooth manifold.  If we instead define a "Lie group" to be a topological manifold such that multiplication and inversion are continuous, is the manifold necessarily smooth?  Is the smooth structure unique if we want a smooth Lie group?  I believe the answer is yes, since a connected Lie group structure is determined by the Lie algebra, but my search attempts failed.