Questions tagged [variance]
The variance tag has no usage guidance.
119
questions
0
votes
0
answers
8
views
1
vote
0
answers
18
views
Whether to use LDA or QDA
I'm trying to determine whether it's best to use linear or quadratic discriminant analysis for an analysis that I'm working on. It's my understanding that one of the motivations for using QDA over LDA ...
- 11
0
votes
1
answer
18
views
VIF Vs Mutual Info
I was searching for the best ways for feature selection in a regression problem & came across a post suggesting mutual info for regression, I tried the same on boston data set. The results were as ...
- 3
1
vote
0
answers
51
views
Why and how Variational Inference underestimates variance?
I referred to the Quora link here as well, but could not understand clearly.
Can anyone please help me understand why and how variational inference underestimates the variance of the true posterior ...
- 51
1
vote
0
answers
20
views
0
votes
1
answer
14
views
How to define the features that bring more variance?
I have a dataset with 10 column, that are my features, and 1732 row that are my registrations. This registration are divided in 15 classes, so I have several registration for every class in my dataset....
- 459
1
vote
1
answer
29
views
How does bias and variance relate with the training/testing error in Machine Learning. In layman terms does high variance means high testing error
What causes high BIAS/VARIANCE and what are the consequences. Can some one explain in simple terms w.r.t to training/testing errors . Thanks
- 11
1
vote
1
answer
57
views
SKLearn PCA explained_variance_ration cumsum gives array of 1
I have a problem with PCA. I read that PCA needs clean numeric values. I started my analysis with a dataset called trainDf with shape ...
- 113
0
votes
0
answers
50
views
PCA in Tensorflow
I am currently trying to understand the code of PCA in TensorFlow Extended. I tried to understand how the Covariance Matrix is calculated once we have a PCollection (Beam). I wanted to execute the ...
- 163
0
votes
1
answer
21
views
Relationship of Bias and size of dataset
I was reading the following book: http://www.feat.engineering/resampling.html where the author mentioned the below:
Generally speaking, as the amount of data in the analysis set shrinks,
the ...
0
votes
2
answers
72
views
Evaluating if metric of one group is higher than the metric of another group when group sizes differ significantly
I am working with a dataset that contains data of applicant income, gender, and loan status (whether or not the person was approved for a loan). I've created the following plots from the data. The ...
- 73
2
votes
1
answer
34
views
learning curves of a classification algorithm
I a trying to understand this learning curve of a classification problem. But I am not sure what to infer. I believe that I have overfitting but I cannot sure.
Very low training loss that’s very ...
- 21
0
votes
0
answers
7
views
Ideas to enforce uniformity of error in linear models
I am looking for ideas to not only solve the least square problem, but to enforce errors to be roughly similar. One idea I had is to add the variance of errors in the classical Ordinary Least Square ...
- 1
1
vote
0
answers
17
views
Repeating values caught with a binary classifier
If my machine is broken, it starts to repeat certain channels. Thing is if there are no out-liars, it is difficult to tell it's broken as we would expect all data points to be around the same value. I ...
- 11
0
votes
0
answers
24
views
Subtraction of two variances (scores)
I was wondering, would it be correct to say, when we treat two variances of two populations as a random variable itself (or as a score), that we can simply get a resultant variance V_subtract = V_pop1 ...
- 11
0
votes
0
answers
21
views
Query regarding variance smoothing in Naive Bayes classification
var_smoothing: float, default=1e-9 -->
Portion of the largest variance of all features that is added to variances for calculation stability.
Source: https://scikit-learn.org/stable/modules/...
- 249
0
votes
0
answers
83
views
Does Bias always decrease when Complexity increase?
(I'm just starting learning about ML stuff and so please don't be rude if the following question is to stupid or totally wrong)
I'm reading about Bias-Variance Trade off and I don't understand the (...
- 51
0
votes
1
answer
13
views
I am not sure whether I am being asked to calculate the variance or the irreducible error
The question:
Suppose we randomly sample a training set D from some unknown
distribution. For each training set D we sample, we train a regression
model to predict $y$ from $x$. We repeat this 10 ...
0
votes
1
answer
24
views
Sampling a data based on average and variance of another data
I have a set of textual datasets that have the following average and variance tokens lengths:
...
- 240
1
vote
0
answers
26
views
Checking my understanding of the bias-variance tradeoff
Hello fellow DS aficionados, I'm trying to clarify some confusing feedback I got from a homework problem.
We were told to recreate the bias-variance tradeoff graph using the first graph below as an ...
1
vote
0
answers
19
views
How can I calculate the level of agreement between my K-Means cluster labels and my ground truth labels in R?
I have made a K-Means clustering from 3 rasters with various values of k (k=2, k=4, k=7) and would like to know which values of k explains the most variance in my ground-truth data or the value of k ...
- 11
0
votes
0
answers
22
views
average of two models with training set N/2 vs one model with training set N
I'm new to ML and I got a question about training model.
Imagine linear regression $Y=\beta^TX+ \epsilon$ and we have training set D (size=N). I have two options:
Train model use whole D and we get $\...
- 1
0
votes
0
answers
24
views
Dividing a data set into segments with consistent inner behavior, using segmentation algorithms and metrics for consistency
Context of the problem:
I have signal data which was recorded in a software system and which shows the runtime of multiple processes over time. In total there are more than 900 processes each having ...
0
votes
0
answers
20
views
Is it always that lower tree with higher bias but higher tree with higher varaince
When dealing with bias and variance trade-offs, I always hear that in tree models:
shallow tree = high bias but low variance,
deep tree = low bias but high variance.
Someone may also quote from high ...
- 11
0
votes
0
answers
116
views
Find variance from 2 variances of 2 datasets with difference sizes
In an attempt to find the mean number of hours his tutorial classmates spent per day preparing
for tutorials, John collected data from 10 of his friends in the tutorial group and found that the
mean ...
- 11
0
votes
0
answers
19
views
How to get variance for regression tree fit?
Suppose the true function is a tree such that:
$$f(x)=\sum_{j=1}^{J}b_j I(x \in R_j)+e_i$$
where $b_j=E(y|x \in R_j)$ ,$E(e_i)=0$ and $R_j$ as terminal node.
Suppose we got a fit for this tree via ...
- 123
0
votes
0
answers
11
views
Generating discriminative features and addressing feature variations across different datasets for same set of data variables?
I am trying to build a classification-based machine learning model using efficient feature selection methods that predict the label of a dependent variable based on few independent variables.
The ...
- 101
0
votes
0
answers
66
views
How do I prevent infinite variances/standard deviations in my variational autoencoder?
I am working on a project with a variational autoencoder (VAE).
The problem I have is that the encoder part of VAE is producing large log variances, which leads to even larger standard deviations, ...
0
votes
0
answers
40
views
Is there R functions that allow to test for overdispersion when fitting a model with survey design?
I realized I need to use the package survey to be able to include sample weights in my regression analysis. Initially, I wanted to use a negative binomial regression on each one of my outcomes as ...
0
votes
1
answer
65
views
dividing Mean by standard Deviation meaning
I have played around with logistic regression a little using movement data intervals that are prelabeled as either resting or active.
I now found that if I divide the mean movement of the individual ...
- 15
1
vote
0
answers
11
views
Generalization error problem on training set
Training data:
$\mathcal {T} =\{(2,1),(3,2),(4,6),(0,0),(1,1)\}$
you already computed a predictor for the output using linear regression by least squares, where you used the first 3 samples as ...
- 11
0
votes
1
answer
33
views
KNN Variance using a high value of K and cross-validation
it has come to my understanding, that a value of K=1, gives a high variance because we are only using only one data point, hence we are very likely to model the noise in that training example.
Bias: ...
0
votes
1
answer
20
views
Lower Variance vs. Higher Validation Scores
So I'm trying to compare between two models, say model(1) has training accuracy of 90% and validation accuracy of 86%, while model(2) has training accuracy of 87% and validation accuracy of 85%.
Now, ...
1
vote
1
answer
39
views
Reducing (Variance) | the gap between my weights
I have ML ready samples. And each sample has a weight.
The weights distribute between [0-1]
My problem arise because there are a lot of samples which are ...
- 121
2
votes
1
answer
25
views
Given a regression based model with many feature variables; what tools would you utilize to figure out which feature variables add the most variance?
Given a hypothetical dataset {S} with 100 X feature variables and 10 predicted Y variables.
X1
...
X100
Y1
....
Y10
1
..
2
3
..
4
4
..
3
2
..
1
Let's say I want to improve the accuracy of Y1. I am ...
3
votes
0
answers
143
views
Unbiasedness of random forests
Suppose that I am trying to build a random forest by subsampling the data and choosing a single feature per tree randomly. For example, suppose there is some dataset,
$D = \{(x_{1},y_{1}), ......(x_{N}...
- 131
0
votes
1
answer
194
views
derivation for expected value for variance
Hi Im taking a course about probability distribution in datascience and below is derivation of the expected value for the variance
Variance = expected value of the squared difference from mean for ...
- 1,181
0
votes
1
answer
24
views
mean and variance of a dataset
I have a simple question. Please see the below screenshot :
It is from a midterm exam from a university : https://cedar.buffalo.edu/~srihari/CSE555/exams/midterm-solution-2006.pdf
My questions is how ...
- 129
0
votes
2
answers
125
views
Figure out relative importance of entity attributes
I'm trying to understand how various aspects of a movie contribute to its gross revenue. I want to rank a movie's attributes in that sense - the attributes that most strongly determine the revenue are ...
- 157
1
vote
0
answers
19
views
KNN with high-variance data [closed]
KNN doesn't work well with high-variance data, so how should I fit my data?
Here is an example of what the data looks like:
- 11
1
vote
0
answers
106
views
Levene test for equal variance
I would like to run one-way ANOVA test on my data. I saw that one of several assumptions for one-way ANOVA is that there needs to be homogeneity of variances. I have run the test for different data-...
- 349
5
votes
2
answers
484
views
Elimination of features based on high covariance without affecting performance?
I ran into a question where the answer ran me into a big doubt.
Suppose we have a dataset $A=${$x1,x2,y$} in which $x1$ and $x2$ are our features and $y$ is the label.
Also, suppose that the ...
- 51
1
vote
1
answer
53
views
Model Selection using Bias Variance Trade Off
I have a Regression Model with Train MAPE as 6% and Test MAPE as 15%.
This appears to me as a clear case of over fitting. But can I still use this model assuming 15% Error is not a bad number after-...
- 11
1
vote
1
answer
193
views
PCA, covariance, eigenvector matrix and rotation [closed]
I am following the Coursera NLP specialization, and in particular the lab "Another explanation about PCA" in Course 1 Week 3.
From the lab, I recovered the following code. It creates 2 ...
- 166
1
vote
1
answer
26
views
Is there a quantitative way to determine if a class of algorithms tends produce low bias or low variance models?
I understand that some machine learning models tend to be low bias, whereas others tend to be low variance (source). As an example, a linear regression will tend to have low variance error and high ...
- 13
0
votes
1
answer
692
views
How can I compute the ideal variance threshold value for my data?
I have a dataset that contains n features scaled between [0,1]. I would use an unsupervised feature selection algorithm (variance thresholding). How can I compute the threshold value?
- 21
1
vote
0
answers
15
views
Confidence interval for class membership probabilities
I would like to calculate confidence intervals for predicted probabilities of a class membership obtained with randomForest.
I know I could use predict.all in randomForest(), which gives me the ...
- 11
1
vote
1
answer
50
views
Find inputs that give highest variance in output space
I have a relatively simple problem that I think should have a known solution, but that I can't figure out. Any help would be greatly appreciated.
Basically, I have a function $f : \mathbb{R}^d \...
- 13
0
votes
0
answers
20
views
How to find a probability distribution the parameters of which do not impact each other like mean and variance in normal distribution do?
I need to find a probability distribution to fit my data. My data has two important features, duration and activity count. Duration means how long one sequence lasts and activity count means the ...
- 207
0
votes
0
answers
35
views
Odd results on bias-variance tradeoff assessment
I am running a bias-variance tradeoff assessment on ten regression models of increasing complexity (linear to x^10), but my results do not satisfy the MSE = Bias^2 + Variance + True Error relationship....
- 21