Questions tagged [statistics]

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1answer
141 views

Simulating coin flips and plotting a histogram

I started playing around recently with F# and I find it quite elegant and succinct language. A common problem I like to solve in every language I start to learn is the coin flip problem, with the ...
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1answer
126 views

Using NumPy to scale data in 2 out of 3 columns

The below code takes a csv containing age, weight, height and prints the betas determined through linear regression to an output csv. It runs for 10 iterations using a different alpha for each, and ...
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1answer
6k views

Obtaining prediction bands for regression model

I'm trying to generate prediction bands for an exponential fit to some 2-dimensional data (available here). The data (blue points), best fit found by ...
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2answers
465 views

Standard deviation from iterators

I want this to be similar to the STL algorithms but I don't find it elegant nor concise at all: ...
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1answer
73 views

Random bits with a specified density (Bernoulli Trials)

I'm sure this is a fully 'solved' problem and expecting cross references but I can't find this on Google. I'm probably missing a keyword. Here is a naive function for populating a ...
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0answers
3k views

Calculate relationship between 2 categorical variables in a pandas Dataset with chi square test

I'm working on a Machine Learning project and I'm in Data Exploration step, and my dataset has both categorical and continuous attributes. I decided to compute a chi square test between 2 categorical ...
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1k views

Rolling z-score function in R

I have written a rolling z-score function myself. Is my implementation of rolling z-score function correct? ...
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0answers
129 views

Kernel density regression in Julia

Here is a naive implementation of a kernel density regression algorithm in Julia. The code works, but there is quite a bit of room for improvement though. First, there is not an optimal bandwidth ...
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4answers
2k views

Calculate odds of winning (UK) Lottery jackpot

I am interested in calculating odds of winning UK Lottery. The format is that 6 numbers from 1-59 are drawn. I am interested only (at this stage) in the odds of winning the jackpot (matching six balls)...
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4answers
16k views

More efficient way of counting the number of values within an interval?

Suppose I have a text file which contains 10,000 random values between 0 and 1, and I want to count the number of values within a specific interval. An example may explain it more clearly. Suppose ...
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4answers
7k views

Monte Carlo coin flip simulation

I've been learning about Monte Carlo simulations on MIT's intro to programming class, and I'm trying to implement one that calculates the probability of flipping a coin heads side up 4 times in a row ...
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2answers
443 views

Two-way ANOVA table

I changed some methods used previously, and I am wondering if I need to do the multiple for loops over and over again. How do I convert my arrays to lists to use in nested ...
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2answers
238 views

Randomly generate a list with predetermined mean

Aim: randomly generate \$n\$ numbers between \$a\$ and \$b\$ with (roughly) mean \$m\$. Problem: The simple beginner's code I wrote becomes very inefficient as \$m\$ moves away from \$\frac{a + b}{2}\...
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2answers
2k views

C++ Int Array/Vector Over 100 Million

Textbook style program that generates the values of two, six-sided dice; which are used to perform simple calculations. Recently, I saw an example using similar criteria that was able to utilize 360,...
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1answer
175 views

Concise Proof of the Monty Hall Problem in R

This is an attempt at a concise proof of the Monty Hall problem in probability and statistics in R. For those unfamiliar, the scenario is this: There exists a contestant on a game show. This ...
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2answers
14k views

Calculating and displaying number statistics

I'm writing a program which takes individual int inputs from the user and then outputs some details on the numbers (average, min, max and how many). Input.readInt() ...
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3answers
311 views

Estimating the number of tanks based on a sample of serial numbers 2.0

There was some confusion with the code I had posted in my previous version of this question and there was some good advice from @Oscar Smith. The explanation is the same; please give improvements for ...
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2answers
838 views

Calculate Geometric and Arithmetic Mean

I am trying to make general class to calculate Geometric mean using exponential of the arithmetic mean of logarithms , and Arithmetic Mean. I am looking for some general feedback on how I can improve ...
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4answers
208 views

Find the locally biggest or equal values including corners in an array

I am looking for a function, that will find in array of n integers highest or equal locally values including corners. My code is probably wrong, and I somehow think solution is in some library like ...
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3answers
206 views

Classifying rows of data by the number of days to close

DataTable looks like below I would like to simplify this code in a better manner. ...
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2answers
4k views

Optimization for histogram computation algorithm in C

Next is an algorithm to calculate the histogram for a given YUV420sp image. The YUV data is given by the hardware camera as an unsigned char*. The algorithms ...
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1answer
1k views

Statistical samples and distributions

It is usually inefficient to find bugs in a longer code. Unfortunately, after spending too much time in debugging my code, I realize that a good programming habit is important. Please give me some ...
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2answers
278 views

Simple and efficient data structure for standard deviation queries in Java

I have this data structure to which the user can add number or remove them, both in constant time. Also, there is a \$O(1)\$ operation for querying the standard deviation of the current contents of ...
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2answers
348 views

Extracting the five most frequent queries from a log file

I'm trying to print the top 5 most queried strings from a text file. I can't use other third-party libraries to make it easier w.r.t hashmap implementations. I need to improve on these if possible: ...
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2answers
546 views

Rolling 100-sided “dice” until they are the same number

I've just begun my journey into python (1 week now) and I've written couple of lines incorporating everything I've learned so far. It would be greatly appreciated if anyone could guide me in writing a ...
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1answer
985 views

Finding the similarity between the two movies using Pearson correlation coefficient

I am trying to find the similarity between the two movies using Pearson correlation coefficient. The programs is working well for small inputs but for large inputs (like 100000 lines) it takes forever....
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3answers
112 views

Extracting sleep quality scores from periodic readings

How can I optimize the next function to work faster? The function must prepare a list to put in a CSV file. The list must contain values of average percentage of sleep per minute counted from ...
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2answers
131 views

On-line evaluation of mean and variance in C#

In various projects, I have to evaluate the mean and/or the variance of relatively large samples. I wrote the following, to help me evaluate these quantities with a constant footprint. Basically, it ...
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1answer
477 views

Coin flips and Dice rolls in a stored procedure

I saw a post in chat a few days ago, of what I thought was an interesting (albeit fairly simple) statistical challenge: By @skiwi: If I shoot once with 50% chance of target A and 50% of target B, ...
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1answer
8k views

Building a histogram array in PHP

I'm visualizing my stored data in an histogram similar to this one: However, I'm sure that my code smells a lot! So I'd like to have your opinion on how to make it better. ...
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2answers
140 views

Pearson Correlation in Haskell

As an exercise to help me learn Haskell, I decided to write a small "program" to find the Pearson Correlation Coefficient for 2 lists of numbers. I'm pretty unhappy with how it turned out, because I ...
4
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1answer
383 views

Optimize a zscore algorithm

I wrote a zscore algorithm in Ruby that runs fine, but is incredibly slow when I have 8000+ entries to score. Can anyone help me figure out a way to improve my code, please? ...
4
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1answer
190 views

Non-overflowing avg calculation with integer arithmetic

I have multiple long values and I want to calculate their average value using integer arithmetic, without precision loss and using java rounding rules for division, ...
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1answer
3k views

Compute Gini Coefficient

Recently, I was given a math assignment to calculate Gini Indexes for a table of percent distributions of aggregate income. The table takes the form of: ...
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1answer
636 views

Find the running median with 2 heaps

I wrote code to solve the running median challenge using 2 heaps, and I'd appreciate any and all feedback. Here is the problem: You have a list of numbers and are scanning them one by one. ...
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1answer
65 views

Average calculator with filters

I am a beginner in Java and I have a hobby project to create a tool for statistical calculations. Users can upload csv with results of a survey. The responses stored in a ...
4
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1answer
62 views

Random distributions in Go with inheritance

I am currently discovering Golang, and I try to implement some random variable generation functions similar to R functions. To avoid code repetition, I'd like to use inheritance, which is quite ...
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2answers
2k views

Find median of two sorted arrays

Problem statement There are two sorted arrays nums1 and nums2 of size m and ...
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3answers
266 views

Rating normalization algorithm

I have a rating system where users can vote between 1-6. I'd like to normalize the votes a bit to better accommodate for extreme voting, where individuals tend to vote as high or as low as possible. ...
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1answer
4k views

Fastest computation of N likelihoods on normal distributions

In the context of a Gibbs sampler, I profiled my code and my major bottleneck is the following: I need to compute the likelihood of N points assuming they have been drawn from N normal distributions ...
4
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1answer
88 views

Evaluate joint probability density function of a Markov random field

The following code evaluates probability mass function for all possible states of a model. ...
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1answer
40 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 ...
4
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1answer
222 views

Averaging accumulator template with overflow detection/prevention

This is a class/template I just wrote for my embedded project (IAR EW ARM - Cortex/ARM7TDMI - Atmel SAM7, SAM4, SAMG). I am gathering data from CAN BUS (FMS), e.g. Engine Revolutions (Per Minute), ...
4
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1answer
81 views

Find line of best fit

This is an update of Test thousands of combinations quickly. I have a physical robot which has a function, turn(degrees). For different robots, there will be small differences in the accuracy of the ...
4
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1answer
253 views

Calculate mean, median, and mode from list of integers

I am trying to solve a problem put in The Rust Programming Language #2 Given a list of integers, use a vector and return the mean (average), median (when sorted, the value in the middle position), ...
4
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1answer
5k views

Calculate “average”, “median” and “percentile” from a long array

I have this method which calculates the average, median and percentile information given a long array of numbers. Is there any better and efficient way to do the same? ...
4
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1answer
78 views

Vectorizing Two Sample Kolmogorov-Smirnov test

I'm implementing the Two-sample Kolmogorov-Smirnov test in MATLAB. I must admit I know very little of formal statistics and was simply trying to implement the description in wikipedia's page. Right ...
4
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1answer
54 views

Generic Timing Class - Follow Up

I wrote a class which can time and compare functions. I already posted it here once before, and got great suggestions from @rolfl, which I have added to my code. my original question can be found ...
4
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1answer
343 views

Bernoulli trials using a condition in a vectorized operation

I was wondering how to vectorize the following code instead of using the for-loop and still be able to check for a condition. ...
4
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1answer
2k views

Averages and standard deviations for a Knn application

I'm working on a small command line application in c# where data is read from a CSV file along with a query and KNN is calculated for the query based on the data. My problem isn't the algorithm at ...