Questions tagged [statistics]

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Generate a large block diagonal covariance matrix with exponential decay

I am implementing Kalman filtering in R. Part of the problem involves generating a really huge error covariance block-diagonal matrix (dim: 18000 rows x 18000 columns = 324,000,000 entries). We denote ...
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A straightforward method for computing the Binomial probability mass function

I've been writing up code to test an alternate way of calculating the Binomial probability mass function. The Binomial random variable is the number of heads out of N coin tosses with coins that have ...
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1answer
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Select optimal piecewise regression fit

I'm making a program which fits a piecewise linear regression with up to 4-5 breakpoints in the data, and then deciding how many breakpoints is best to prevent over and underfitting. However, my code ...
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2answers
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Calculate mean and standard error of a generator in Python

The goal of the following code is to calculate the mean and the standard error of vectors of randomly-generated numbers. I am looking for feedback both on the correctness of the calculation, and on ...
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Counting co-occurence of a file encoded in UTF-8 [closed]

I need to write a script that can count co-occurences in a UTF-8 encoded file. The length of the co-ocurence is between 2 to ...
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Simple Kivy App for Bootstrap Algorithm

I have a very simlpe app built using Kivy, for performing bootstrap algorithm (statistics). We must input some samples in the form x1,x2,...,xn (these will be ...
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1answer
54 views

Generating Latin hypercube samples with numpy

I wrote some code to generate Latin hypercube samples for interpolation over high-dimensional parameter spaces. Latin hypercubes are essentially collections of points on a hypercube that are placed on ...
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1answer
26 views

Manual Regression Tree using Python

I wrote a code to create a regression tree for a synthetic train data of size Np. The idea is, first I have the source node (which consists of all set of points) ...
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28 views

Sortings stocks into quantiles based on their signal

This function sorts stocks into quantiles. To do so I used this function that accepts sig_df (dataframe with the timeseries of stocks signal) and number of ...
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1answer
59 views

Pick the best combination of n choose k models

Algorithm Let \$M_0\$ denote the null model which contains no predictors. This model simply predicts the sample mean of each observation. For \$k=1,2,\ldots,n\$: Fit all \$n \choose k\...
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1answer
35 views

Entropy calculation function in Haskell

I've written a function in Haskell for calculating the entropy of a collection. I'd like feedback on how the function could be rewritten to be more flexible/reusable, and also how to profile the ...
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1answer
1k views

HackerRank: Climbing the Leaderboard

Below is my solution to Climbing the Leaderboard on HackerRank: Alice is playing an arcade game and wants to climb to the top of the leaderboard. Can you help her track her ranking as she beats ...
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Bias-corrected percentile Bootstrapping Optimization

I have never posted to this forum, but was referred here. I need some help printing key iterations as well as optimizing my code for run time. If someone had some time to help/explain how to correct ...
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Calculate min, max, mean and median out of array

Another C exercise: Write a function that takes an array of 'ints' as its input and finds the smallest and largest elements. It should also compute the median and mean. Use a ...
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3answers
107 views

Statistical methods using PHP (mean, co/variance, standard deviation, skew, correlation)

Functionality This class has a list of statistical functions such as mean, variance, standard deviation, skewness, and it works okay. These functions are applied to arrays of charts data. It is an ...
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1answer
92 views

Groovy script to get average price per group from different data arrays

I've been trying to learn Groovy lately and I tried to solve a problem which involves designing a routine that will calculate the average Product price per Group. I have the following data: ...
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1answer
272 views

R function for Dynamic Ordinary Least Squares regression

SHORT VERSION: Made a workflow function, want a better output with methods. General Background I have been working on a package for some time to eliminate the tedium of preliminary time series ...
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28 views

Flagging out-of-stock items

I wrote a function that iterates over 3 parameters to spot out-of-stock items. To illustrate this I'll draw an example: suppose that the product 10 in store 2 for an offer named "super5" is following ...
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1answer
169 views

Summarizing downtime statistics

I am not satisfied with the performance and especially the time my piece of code takes to complete. The surrounding environment for better understanding is the following: A statistic for Downtime ...
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0answers
19 views

TensorFlow regressor to predict probability of winning, given a current score

This is a TensorFlow regressor that tells me that if you get x score, you will have x% to win a game in x game(game is not important). Doing this as a project to learn tensorflow. ...
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1answer
96 views

Rolling mean lag function for multiple variables

Thanks to @josliber's help (Rolling mean lag function), I was able to speed up a rolling mean function for different groups and rollmean lengths. Now I'd like to add to this function the ability to ...
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2answers
2k views

Rolling regressions in R

I want to run rolling regressions over each group and store the coefficient. The following works, but it's slow, since I have too many series and I want to run too many regressions for each group. ...
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2answers
159 views

Finding median from unsorted array with duplicate elements without sorting it

I am implementing a method to find the median of an unsorted array using a counting sort. I would happily go for a median of medians or selection algorithm for better performance but they are ...
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1answer
101 views

Calculating difference statistics over a moving window

I'd like to calculate some statistics of given data (frequencies of difference among elements on various distances in percent multiplied by 10) using moving window within that data. Is it possible to ...
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3answers
121 views

Computing average duration per user from a large CSV file that doesn't fit in memory

We have a large log file which stores user interactions with an application. The entries in the log file follow the following schema: {userId, timestamp, actionType} where actionType is one of two ...
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1answer
855 views

Django Rest Framework Totaling API values in different ways

I am working on a stats website for my softball teams that I manage/play for. Here is my current Stat model: ...
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0answers
50 views

Lazy Statistics: XYSamples java

After previous review I chose to alter this project to use lazy evaluation. Looking for any and all improvement feedback. This project is meant to represent a two dimensional data set, i.e., single-...
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1answer
90 views

Program which accepts grades and prints grade distribution

I'm doing the MOOC Java course (CTRL+F "distribution"): The input of the program is a set of exam scores of a course. Each score is an integer. When -1 is entered, the program stops asking for ...
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1answer
69 views

Monte Carlo errors estimation routine

I would value your opinion on the following piece of code. I am rather new to both Python and Monte Carlo analysis, so I was wondering whether the routine makes sense to more experienced and ...
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1answer
92 views

Welford's online variance calculation algorithm for vectors

I'm developing a face recognizing application using the face_recognition Python library. The faces are encoded as 128-dimension floating-point vectors. In addition to this, each named known person ...
3
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1answer
62 views

Generating random number from a binomial distribution

In my application of Monte Carlo simulation, the crucial part is to generate a random number from a binomial distribution with parameters n = size and p = 0.5. Here is my current implementation ...
3
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1answer
37 views

Sample size, P-values (its relationship), and data visualization with plots. ggplot and T test

We know that P-values (within t-test context as an example..) is highly sensitive to sample size. A larger sample will yield a smaller p-value remaining everything else constant. On the other hand, ...
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1answer
69 views

Incrementing time in a discrete-event simulation of a supermarket queue

A method has been written that increments time in minutes that simulates how much time it takes to process item in a supermarket queue and if there is an empty queue, skip it and loops around to find ...
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1answer
48 views

Python implementation of approximating the chance a particle is at a location after n steps in the cardinal directions

Recently, I became very interested in a probability practice problem in my textbook for my class. I decided to implement it in code and I think I got most of it implemented. Right now, I'm hoping to ...
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2answers
26k views

Calculating population standard deviation

This is a script I have written to calculate the population standard deviation. I feel that this can be simplified and also be made more pythonic. ...
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2answers
78 views

Constructing a cumulative distribution function from a histogram

During some running process, a histogram of values shall be build up. When done, the CDF shall be derived from it and used to get the quantiles for some values. My current implementation looks as ...
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1answer
69 views

Evaluating association strengths of items

I have a list of animals with their counts: ...
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0answers
23 views

Simple data analysis for forecasting

This Python script extracts data from txt files containing raw numerical data, notably the increase average, the relative evolution and the standard deviation of ...
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1answer
62 views

Linear regression on points specified by the user in a GUI

Here's my take on the Linear Regression exercise from John Zelle's Python book. Open a window, let the user click on as many points as they want. Upon pressing the "Done" button the regression line ...
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2answers
77 views

Application to monitor device power levels for deviations

I have a high performance, computation intensive application that runs on a Centos 7 machine with Python 2.7.5. I'll try to explain what the application does: The application runs an infinite loop, ...
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0answers
46 views

Download and analyze PDFs of Congressional records

This is built with Python 2.7.15. The goal of this script is to count the number of words spoken by each Senator on the floor of Congress between given dates. It pulls from the Congressional Record, ...
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2answers
378 views

Counting consecutive selections of a given number when sampling integers in a range

This script counts consecutive number strikes of a number that you determine in a number-sequence that you also determine. I would be very pleased if this script can be reviewed in terms of ...
3
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1answer
81 views

Plots of prior and posterior distributions for a model

I have an exercise that ask to plot the prior and posterior distribution in the Poisson-Gamma model. I did it (I think it's correct) inspired in the answer of this question https://stats.stackexchange....
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2answers
1k views

Normal distribution array function

I have a function that produce an array with values that are Gaussian (normal) distribution. If you plot the values on a graph, it would look something like this: Is there any way to improve on the ...
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1answer
74 views

Simulating data generating process correctly

My aim is to simulate the following model by means of a Monte Carlo simulation. I wonder if my R code is correct for generating the data. Could somebody check? The model: $$Y = \sum_{j=1}^{100} (...
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1answer
40 views

Generating probability table of 2-character combinations from text file in Java

I have written a probability table generator in Java to help me generate randomized girl's names for the game I am making. It reads from a text file and creates a ...
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0answers
2k views

A Simple K-Means Cluster Analyzer v0.1

[NOTE] This question can be depreciated in favor of version 0.2. This code works well. This my first attempt at creating a robust, computationally lean K-Means Cluster analyzer. I first saw this ...
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3answers
107 views

A collection of vector functionals

I would like some feedback for a collection of what I call "vector functionals", by which I mean maps \$\ell\colon \mathbb{K}^{n} \to \mathbb{K}\$, where the field \$\mathbb{K} = \mathbb{R}\$ or \$\...
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4answers
16k views

Finding the mode of an array

I am a beginner in JavaScript and just wanted to get my code reviewed. Here I have created a function that takes in an array and returns the mode. If there is no more then I just want the function to ...
8
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2answers
468 views

Sparse 3D binning/histogram function

This is a function written in Python I wrote to process galaxy catalogs for cosmology research, however it is more generally applicable than just my pipeline. The goal is to take a Python list of ...