variance Questions

15

I'm trying to find an efficient, numerically stable algorithm to calculate a rolling variance (for instance, a variance over a 20-period rolling window). I'm aware of the Welford algorithm that eff...
Gobetween asked 28/2, 2011 at 20:46

0

This is both a question and a poll. Considering the following case: trait Mat[+T] implicitly[Mat[Product] =:= Mat[_ <: Product]] /* Compiler error: : Cannot prove that com.tribbloids.spike.d...
Exponible asked 7/5, 2023 at 18:31

5

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I wasn't sure if this should go in SO or some other .SE, so I will delete if this is deemed to be off-topic. I have a vector and I'm trying to calculate the variance "by hand" (meaning based on th...
Tallahassee asked 20/2, 2015 at 20:49

4

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I have survey data from a stratified simple random sampling design where some strata contain only a single sampling unit (even though the strata population size may be >1). These are referred to as...
Bushwa asked 11/9, 2015 at 23:49

1

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I have a function that expects a short lived object. I would expect that I would be able to always pass it a long lived object. But I am getting a strange error when I try to encode that: type F&lt...
Hydrokinetic asked 18/8, 2022 at 19:8

9

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If I have a list like this: results=[-14.82381293, -0.29423447, -13.56067979, -1.6288903, -0.31632439, 0.53459687, -1.34069996, -1.61042692, -4.03220519, -0.24332097] I want to calculate the va...
Pushkin asked 23/2, 2016 at 16:47

6

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I have a simple time series and I am struggling to estimate the variance within a moving window. More specifically, I cannot figure some issues out relating to the way of implementing a sliding win...
Parthenia asked 11/12, 2014 at 16:22

2

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As I understand it when creating a supervised learning model, our model may have high bias if we are making very simple assumptions (for example if our function is linear) which cause the alg...

4

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@uncheckedVariance can be used to bridge the gap between Scala's declaration site variance annotations and Java's invariant generics. scala> import java.util.Comparator import java.util.Compar...
Outhe asked 16/3, 2010 at 12:33

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So, I've posted a few times and previously my problems were pretty vague. I started C++ this week and have been doing a little project. I'm trying to calculate standard deviation & variance. My...
Aidoneus asked 21/10, 2015 at 20:20

1

I fitted a linear mixed model to agricultural data, accounting for unequal variances across groups (cultivars) by passing weights = varIdent(...) to lme. lsmeans is showing standard errors that do ...
Claustrophobia asked 22/1, 2022 at 2:30

3

I am working with sklearn and specifically the linear_model module. After fitting a simple linear as in import pandas as pd import numpy as np from sklearn import linear_model randn = np.random.ra...
Butternut asked 13/3, 2014 at 14:20

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I want to extend Welford's online algorithm to be able to be updated with multiple numbers (in batch) instead of just one at a time: https://en.wikipedia.org/wiki/Algorithms_for_calculating_varianc...
Doak asked 1/6, 2019 at 0:23

2

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Consider this short snippet: trait Table[+A] { type RowType = Seq[A] } Scala 2.11.7 compiler gives the following error: covariant type A occurs in invariant position in type Seq[A] of type Row...
Careerist asked 1/11, 2015 at 2:57

4

Looking for a way to calculate Population Standard Deviation in R -- using greater than 10 samples. Unable to extract the source C code in R to find the method of calculation. # Sample Standard De...
Skied asked 3/6, 2017 at 0:24

3

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In a Python program, I need to generate normally-distributed random numbers with a specific, user-controlled variance. How can I do this?
Responsible asked 11/1, 2012 at 7:34

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Edit:: after all these discussions with juanpa & fusion here in the comments and Kevin on python chat , i have come to a conclusion that iterating through a generator takes the same time as it ...
Oconnell asked 2/9, 2020 at 4:21

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I have rather huge dataset in which I would like to exclude columns with a rather low variance, which is why I would like to use the phrase NearZeroVar. However, I do have some trouble understandin...
Defecate asked 15/6, 2020 at 16:26

2

This should be very basic and I hope someone can help me. I ran a principal component analysis with the following call: pca <- princomp(....) summary(pca) Summary pca returns this description...
Meenen asked 14/3, 2015 at 1:38

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Simply, I am trying to calculate the sharpness of an image as a part of a function in C# using OpenCVSharp. As the 1st try, I used Laplacian Filter like this: int kernel_size = 3; int scale = 1; ...
Whereby asked 19/9, 2019 at 6:40

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I am trying to make a function that prints the variance of a list of defined numbers: grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5] So far, I have tried proceeding on making...
Vilify asked 21/5, 2013 at 13:0

1

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I've followed the advice laid out here for calculating the average of circular data: https://en.wikipedia.org/wiki/Mean_of_circular_quantities But I'd also like to calculate standard deviation as...
Contend asked 10/4, 2019 at 15:50

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How can I calculate the population variance of my data using R? I read there is a package called popvar but I have the Version 0.99.892 and I don't find the package
Intinction asked 9/6, 2016 at 18:7

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The C# spec states that an argument type cannot be both covariant and contravariant at the same time. This is apparent when creating a covariant or contravariant interface you decorate your type p...
Fillip asked 24/12, 2010 at 20:22

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What does the statement mean? From here ref and out parameters in C# and cannot be marked as variant. 1) Does it mean that the following can not be done. public class SomeClass<R, A>:...
Hennessey asked 20/5, 2010 at 17:33

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