probability

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 How to treat p value in R ? I am expecting very low p values like: 1.00E-80 I need to -log10 -log10(1.00E-80) -log10(0) is Inf, but Inf at sense of rounding too. But is seems that after 1.00E-308, R yields 0. 1/10^308 [1] 1e-308 1/10^309 [1] 0 Is the accuracy of p-value display with lm function the same as the cutoff point, 1e-308, or it is just designed such that we need a cutoff point and I need to consider a different cutoff point - such as 1e-100 (for example) to replace 0 with <1e-100.

问题 It is known that GBT s in Spark gives you predicted labels as of now. I was thinking of trying to calculate predicted probabilities for a class (say all the instances falling under a certain leaf) The codes to build GBT's import org.apache.spark.SparkContext import org.apache.spark.mllib.regression.LabeledPoint import org.apache.spark.mllib.linalg.Vectors import org.apache.spark.mllib.tree.GradientBoostedTrees import org.apache.spark.mllib.tree.configuration.BoostingStrategy import org.apache

问题 I have a problem involving a collection of continuous probability distribution functions, most of which are determined empirically (e.g. departure times, transit times). What I need is some way of taking two of these PDFs and doing arithmetic on them. E.g. if I have two values x taken from PDF X, and y taken from PDF Y, I need to get the PDF for (x+y), or any other operation f(x,y). An analytical solution is not possible, so what I'm looking for is some representation of PDFs that allows such

问题 I want to generate a random number with a given probability but I'm not sure how to: I need a number between 1 and 3 num = ceil(rand*3); but I need different values to have different probabilities of generating eg. 0.5 chance of 1 0.1 chance of 2 0.4 chance of 3 I'm sure this is straightforward but I can't think of how to do it. 回答1: The simple solution is to generate a number with a uniform distribution (using rand), and manipulate it a bit: r = rand; prob = [0.5, 0.1, 0.4]; x = sum(r >=

问题 I'm looking for the best way of implementing random number generator, that will allow me to have control over probability from what range the generated number will be returned. To visualize what I'm trying to achieve I have a picture : So to summarize : Let's say that my range is 400. At the beginning I'd like to have 5% probability of getting number 0-20. But at some moment in time I'd like to have this probability increased up to 50%. Hope you get the idea. 回答1: Hmm, working on your

问题 I'm looking for the best way of implementing random number generator, that will allow me to have control over probability from what range the generated number will be returned. To visualize what I'm trying to achieve I have a picture : So to summarize : Let's say that my range is 400. At the beginning I'd like to have 5% probability of getting number 0-20. But at some moment in time I'd like to have this probability increased up to 50%. Hope you get the idea. 回答1: Hmm, working on your

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: C++ function for picking from a list where each element has a distinct probability I need to randomly determine a yes or no outcome (kind of a coin flip) based on a probability that I can define (.25, .50, .75). So for example, I want to randomly determine yes or no where yes has a 75% chance of being chosen. What are my options for this? Is there a C++ library I can use for this? 回答1: You can easily implement

问题 How can i generate a random number between A = 1 and B = 10 where each number has a different probability? Example: number / probability 1 - 20% 2 - 20% 3 - 10% 4 - 5% 5 - 5% ...and so on. I'm aware of some hard-coded workarounds which unfortunately are of no use with larger ranges, for example A = 1000 and B = 100000. Assume we have a Rand() method which returns a random number R, 0 < R < 1, can anyone post a code sample with a proper way of doing this ? prefferable in c# / java /

问题 How can i generate a random number between A = 1 and B = 10 where each number has a different probability? Example: number / probability 1 - 20% 2 - 20% 3 - 10% 4 - 5% 5 - 5% ...and so on. I'm aware of some hard-coded workarounds which unfortunately are of no use with larger ranges, for example A = 1000 and B = 100000. Assume we have a Rand() method which returns a random number R, 0 < R < 1, can anyone post a code sample with a proper way of doing this ? prefferable in c# / java /