statistics

问题 I have an array of cartesian points (column 1 is x values and column 2 is y values) like so: 308 522 307 523 307 523 307 523 307 523 307 523 306 523 How would I go about getting a standard deviation of the points? It would be compared to the mean, which would be a straight line. The points are not that straight line, so then the standard deviation describes how wavy or "off-base" from the straight line the line segment is. I really appreciate the help. 回答1: If you are certain the xy data

问题 Summing up my understanding of the topic 'Dummy Coding' is usually understood as coding a nominal attribute with K possible values as K-1 binary dummies. The usage of K values would cause redundancy and would have a negative impact e.g. on logistic regression, as far as I learned it. That far, everything's clear to me. Yet, two issues are unclear to me: 1) Bearing in mind the issue stated above, I am confused that the 'Logistic' classifier in WEKA actually uses K dummies (see picture). Why

问题 I have a classification tree analyzed using ctree() was wondering how can one rotate the terminal nodes so that the axes are vertical? library(party) data(iris) attach(iris) plot(ctree(Species ~ Sepal.Length + Sepel.Width + Petal.Length + Petal.Width, data = iris)) 回答1: Here is how I would go about it. Not the shortest answer, but I wanted to be as thorough as possible. Since we are plotting your tree, it's probably a good idea to look at the documentation for the appropriate plotting

问题 I have a classification tree analyzed using ctree() was wondering how can one rotate the terminal nodes so that the axes are vertical? library(party) data(iris) attach(iris) plot(ctree(Species ~ Sepal.Length + Sepel.Width + Petal.Length + Petal.Width, data = iris)) 回答1: Here is how I would go about it. Not the shortest answer, but I wanted to be as thorough as possible. Since we are plotting your tree, it's probably a good idea to look at the documentation for the appropriate plotting

问题 This self-answered question is a follow-up to this question: How can I determine a given dataset's (array's) statistical mode, i.e. the one value or the set of values that occur most frequently? For instance, in array 1, 2, 2, 3, 4, 4, 5 there are two modes, 2 and 4 , because they are the values occurring most frequently. 回答1: Use a combination of Group-Object , Sort-Object , and ForEach-Object : # Sample dataset. $dataset = 1, 2, 2, 3, 4, 4, 5 do { # dummy loop to allow efficient termination

问题 I'm currently testing GAs new async code snippet using two different tracking codes on the same page; _gaq.push( ['_setAccount', 'UA-XXXXXXXX-1'], ['_trackPageview'], ['b._setAccount', 'UA-XXXXXXXX-2'], ['b._trackPageview'] ); Although both codes work, I've noticed that they present inconsistent results. Now, we aren't talking huge differences here, only 1 or 2 visits / day every now and then. However, this site is tiny and 1 or 2 visits equates to a 15% difference in figures. Now, the final

问题 This question already has answers here : Closed 9 years ago . Possible Duplicates: Random weighted choice Generate random numbers with a given (numerical) distribution I have a list of list which contains a series on numbers and there associated probabilities. prob_list = [[1, 0.5], [2, 0.25], [3, 0.05], [4, 0.01], [5, 0.09], [6, 0.1]] for example in prob_list[0] the number 1 has a probability of 0.5 associated with it. So you would expect 1 to show up 50% of the time. How do I add weight to

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . Anyone know of a good statistics library for C? I'm looking for something that is commonly used and not a small project. EDIT: must be free! 回答1: gsl (http://www.gnu.org/software/gsl/) is widely available, portable, and has a lot of nice functionality. 回答2: Statistics are frequently done in other languages, but

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 9 years ago . Which one among the two languages is good for statistical analysis? What are the pros and cons, other than accessibility, for each? 回答1: MATLAB Good for beginners Good for interactive sessions Python (with SciPy)

问题 Using any tools which you would expect to find on a nix system (in fact, if you want, msdos is also fine too), what is the easiest/fastest way to calculate the mean of a set of numbers, assuming you have them one per line in a stream or file? 回答1: Awk awk '{total += $1; count++ } END {print total/count}' 回答2: awk ' { n += $1 }; END { print n / NR }' This accumulates the sum in n , then divides by the number of items ( NR = Number of Records). Works for integers or reals. 回答3: Using Num-Utils