standard-deviation

I wish to clarify upfront I am looking for a way to calculate Standard deviation using Streams (I have a working method at present which calculates & returns SD but without using Streams). The dataset i am working with matches closely as seen in Link . As shown in this link am able to group my data & get the average but not able to figure out how to get the SD. Code outPut.stream() .collect(Collectors.groupingBy(e -> e.getCar(), Collectors.averagingDouble(e -> (e.getHigh() - e.getLow())))) .forEach((car,avgHLDifference) -> System.out.println(car+ "\t" + avgHLDifference)); I also checked Link

Below you can see my C# method to calculate Bollinger Bands for each point (moving average, up band, down band). As you can see this method uses 2 for loops to calculate the moving standard deviation using the moving average. It used to contain an additional loop to calculate the moving average over the last n periods. This one I could remove by adding the new point value to total_average at the beginning of the loop and removing the i - n point value at the end of the loop. My question now is basically: Can I remove the remaining inner loop in a similar way I managed with the moving average?

i found the following code snippet here on stackoverflow, but i have the problem that the stdev becomes NaN. Any ideas how to fix this? public static void AddBollingerBands(ref SortedList<DateTime, Dictionary<string, double>> data, int period, int factor) { double total_average = 0; double total_squares = 0; for (int i = 0; i < data.Count(); i++) { total_average += data.Values[i]["close"]; total_squares += Math.Pow(data.Values[i]["close"], 2); if (i >= period - 1) { double total_bollinger = 0; double average = total_average / period; double stdev = Math.Sqrt((total_squares - Math.Pow(total

Normally, I have a more technical problem but I will simplify it for you with an example of counting balls. Assume I have balls of different colors and one index of an array (initialized to all 0's) reserved for each color. Every time I pick a ball, I increment the corresponding index by 1. Balls are picked randomly and I can only pick one ball at a time. My sole purpose is to count number of balls for every color, until I run out of balls. I would like to calculate standard deviation of the number of balls of different colors, while I am counting them . I do not want to calculate it by having

I want to find mean and standard deviation of 1st, 2nd,... digits of several (Z) lists. For example, I have A_rank=[0.8,0.4,1.2,3.7,2.6,5.8] B_rank=[0.1,2.8,3.7,2.6,5,3.4] C_Rank=[1.2,3.4,0.5,0.1,2.5,6.1] # etc (up to Z_rank )... Now I want to take the mean and std of *_Rank[0] , the mean and std of *_Rank[1] , etc. (ie: mean and std of the 1st digit from all the (A..Z)_rank lists; the mean and std of the 2nd digit from all the (A..Z)_rank lists; the mean and std of the 3rd digit...; etc). Bengt Since Python 3.4 / PEP450 there is a statistics module in the standard library, which has a method

I'm very new here, at the moment I am trying to calculate standard deviation with Java (I have googled it haha) but I am having a lot of issues on getting it working I have ten values that are inputed by a user which I then have to calculate the standard deviation of my understanding so far thanks to people who have replied is I find the mean of the array then complete the calculations double two = total[2]; double three = total[3]; double four = total[3]; double five = total[4]; double six = total[6]; double seven = total[7]; double eight = total[8]; double nine = total[9]; double ten = total

I would like to reproduce the following figure in MATLAB: There are two classes of points with X and Y coordinates. I'd like to surround each class with an ellipse with one parameter of standard deviation, which determine how far the ellipse will go along the axis. The figure was created with another software and I don't exactly understand how it calculates the ellipse. Here is the data I'm using for this figure. The 1st column is class, 2nd - X, 3rd - Y. I can use gscatter to draw the points itself. A = [ 0 0.89287 1.54987 0 0.69933 1.81970 0 0.84022 1.28598 0 0.79523 1.16012 0 0.61266 1

I am trying to calculate Z-scores using PHP. Essentially, I am looking for the most efficient way to calculate the mean and standard deviation of a data set (PHP array). Any suggestions on how to do this in PHP? I am trying to do this in the smallest number of steps. to calculate the mean you can do: $mean = array_sum($array)/count($array) standard deviation is like so: // Function to calculate square of value - mean function sd_square($x, $mean) { return pow($x - $mean,2); } // Function to calculate standard deviation (uses sd_square) function sd($array) { // square root of sum of squares