obtain some of the best features (most closely related to Y) after dimensionality reduction ), what should we do?
2. Linear Discriminant Analysis (Case 2)
Review our previous logistic regression method. Given m n-dimensional feature training samples (I from 1 to m), each corresponds to a class label. We just need to learn the parameters so that (G is the sigmoid function ).
Now we only consider binar
Note: This article is not the author's original, original Reprinted from: http://blog.csdn.net/porly/article/details/8020696
1.What is lda?
Linear Discriminant Analysis (LDA. Fisher Linear Discriminant (linear) is a classic algorithm for pattern recognition. In 1996, belhumeur introduced Pattern Recognition and AI.
The basic idea is to project a high-dimensiona
Huadian North Wind BlowsKey laboratory of cognitive computing and application, Tianjin UniversityDate: 2015/12/11
The Gaussian discriminant analysis belongs to the generative model, and the model finally learns a characteristic-class joint probability.
0 multi-dimensional normal distributionTo determine a multidimensional normal distribution only need to know the distributed mean Vector μ∈rnx1 \mu\in r^{n
Brief introduction
IBM SPSS Modeler Entity Analytics (EA) is a new feature added to IBM's SPSS Modeler 15.0 based on the IBM SPSS Modeler 14.2 Predictive analysis. Compared with traditional Modeler, Entity Analytics has a new dimension for data prediction. IBM's SPSS Modele
The amount of distance on a blog has been a long time, has been busy to do a job, recently finished, or to write blog ah. A lot of basic knowledge some forgotten, also counted as a kind of review. I try to derive the key place to write, suggesting that you still want to manually push a formula to increase understanding.
Linear discriminant Analysis (also known as Fisher Linear
Original: http://sebastianraschka.com/Articles/2014_python_lda.htmlCompiling: Asher Li
Note 1: In this paper, the linear algebraic term "eigenvalue" and "eigenvector" are presented, and the Chinese textbooks have two common translation methods of "eigenvalue" and "intrinsic value". In order to differentiate with "feature", this article uses "intrinsic" translation.
Note 2: The paper mentions "Kxd k \times D-Wieben vector Matrix", the original writing "Kxd K \times d-dimensional Matrix", which re
') plt.ylabel (' Ratio_sugar ') plt.title (' LDA ') plt.show () W=calulate_w () plot (W)The results are as follows: The corresponding W value is:[ -6.62487509e-04, -9.36728168e-01]Because of the relationship between data distribution, LDA's effect is not obvious. So I changed the number of samples of several label=0, rerun the program to get the result as follows:The result is obvious, the corresponding W value is:[-0.60311161,-0.67601433]Transferred from: http://cache.baiducontent.com/c?m= 9d7
:
Krumbach a reliability coefficient is the most commonly used reliability coefficient at present. The formula is: a= (k/k-1) * (∑SI2)/st2)Among them, K is the total number of the items in the scale, SI2 is the variance of the problem in the first question, ST2 is the variance of the total score of all the titles. It can be seen from the formula that the evaluation of a coefficient is the consistency between the scores of each item in the scale, which belongs to the intrinsic consistency coeffic
in the R language, linear discriminant analysis (Liner discriminant analyses, or LDA) is implemented by using thelinear discriminant function Lqa () in the package mass. The function has three invocation formats:1) When the object is data.frame the data frameLDA (X,grouping,prior = Propotions,tol = 1.0E-4,METHOD,CV = F
separate process, also retained the old dialog box, the New dialog box according to the sample situation classification, according to the sample situation to choose methods, and more inclined to automated analysis, The classification of the old dialog box is not very clear, we will follow the new dialog box to introduceAnalysis-non-parametric inspection-single sampleI. Single sample 1. The two-item test, two-item test, also known as two-item distribu
decomposed into 3 parts: the sum of squares caused by the individual action of multiple control variables; the sum of squared deviations caused by the interaction of multiple control variables; the sum of squared deviations caused by other stochastic factors3. Covariance analysis: It is difficult to control the factors as a co-variable, in the context of the influence of the dispatch of the covariance, analysis
The T-Test in SPSS is all concentrated in the analysis-compare mean menu. About the T-Test again, we know that a statistical result needs to be expressed in three parts: concentration, variability, and significance.The centralized performance indicator is the mean valueVariance, standard deviation, or standard error is the performance indicatorThe significance is to determine whether to achieve the signific
require that there is no correlation between the independent variables, that is, there is no multiple collinearity. However, there is no relevant two variables that are not present, so the conditions are relaxed to be acceptable as long as they are not strongly correlated.Multiple linear regression in the process of SPSS and simple linear regression, just the content of a few more, and because of the more information, it is recommended to set the
The first satisfying condition of linear regression is the linear relationship between the dependent variable and the independent variable, and then the fitting method is based on it, but if the dependent variable and the independent variable are nonlinear, then the nonlinear regression is needed to analyze it.There are two processes that can be called in the nonlinear regression of SPSS, one is analysis-re
Linear regression is most commonly used as a fitting method with least squares, but the method is more susceptible to strong influence points, so when we fit the linear regression model, we also take the strong influence point as the condition to be considered. For strong-impact points, a more robust fit method is needed in cases where it cannot be corrected or deleted, and the least-squares method is the solution to such problems.The least square method is due to the residual sum of squares, an
Lofistic regression model can also be used for pairing data, but its analysis methods and operation methods are different from the previous introduction, the specific performanceIn the following areas1. Each pairing group has the same regression parameter, which means that the covariance function is the same in different paired groups2. The constant term varies with the pairing group, reflecting the role of non-experimental factors in the pairing grou
In the process of SPSS nonlinear regression, we talked about the loss function button can customize the loss function, but there is a constraint button is not mentioned, the function of the button is to self-The parameter setting condition of the loss function is defined, these conditions are usually composed of the logical expression, which makes the loss function have certain judgment ability.The main function of this function is to carry out piecew
probability distribution. Mathematical Expectations to and Covariance matrix for the one Random Variables of the multivariate normal distribution. Joint probability density function to beObey multivariate normal distribution can be recorded as.If, and, then.can see that Multivariate normal distribution is related to two quantities: mean and covariance matrices. So, next, look at the changes that are caused by changing the values of these two quantities through an image.
1. Gau
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